windows 2000 hanging while starting. Mup.sys cause?

My windows was working fine, but all of a sudden IT is hanging while starting, when I started to start in safemode, It is coming upto verification of c:\winnt\system32\drivers\mup.sys and hanging.

What shall I do. I tried to restore the windows using CD but it didnot work. I renamed the mup.sys as mup1.sys and copied the mup.sys from another system using recovery console, Even then the problem is persistent.

Finally I decided enough is enough and went with new installation of windows. to my horror at the startup I am not getting usual (windows 2000 (setup)). Instead three lines of same windows 2000 operating system. and each hang at the same mup.sys.

How shall I resolve the problem.
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moduloConnect With a Mentor Commented:
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pappalaAuthor Commented:
I have formatted the C:\ Drive. I have removed all partitions and recreated them. Still the problem is persistent. Is it problem with hardware?
Check for a boot sector virus, boot sector viruses can sometimes casue windows setup to act wierd. There should be an option in your bios to scan the bootsector at startup. Usually under Advanced Options in award bios. If this is not the case i recommend a DOD format or a low level format which can be obtained from the drive's manufacturer or using parition magic, if the problem still persists it may point to a bad sector or head on the hard drive.
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did u try to reply?
oops typo.. I mean did u try repair
According that what I've read, this problem might be caused by one or more of your PCI cards. Try removing all of your PCI devices except for your video card and see if that solves the problem. If it does, then you can try putting the PCI cards back in one-by-one until you find the one that causes the problem.
IO device cards like USB and SCSI are your most likely source of the problem.
You might wanna try this to clear your drive.
I had this same problem in Windows XP and finally figured out what fixed it
in my case.  I couldn't boot regularly, safe mode, from the XP CD, etc.  I
had no way of getting into the system!

The USB problems people have mentioned on various message boards prompted
me to check my usb mouse out.  It's an optical mouse so I could try it in
another machine and tell immediately whether it was working (since it lit
up).  Unplugging it and plugging it in again while the machine was off
didn't help.  But when I got to the mup.sys line while safe mode was
booting I unplugged the USB mouse and the machine continued to boot!  I now
have the mouse plugged in and it reboots with no problems.

So, yet one more thing to try; unplug all of your USB devices after the
mup.sys line appears.  It may just continue!
Don't blame mup.sys.
It just happens that it is the last line put on the screen in safe mode before the GUI starts. Most likely something in the GUI is causing the problem. I just fixed a system that was hanging at mup.sys, it was caused by faulty memory.  
1) disable USB (from the BIOS usually) if possible.
2) if 1 didn't work, Boot use your Windows 2000 disk and use the 'repair' option

but what STeve7000 said is interesting, if true, any recommendation you get will be a shot in the dark, if it's not actually related to MUP.sys then the problem as described in the link above may have nothing to do with your issue.  Try 2).  

I'm working on the same problem now on a w2k pro box...
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Boot from your windows cd
Press "R" to load the recovery console
Select the Windows installation to be repaired
Enter administrator password if necessary and hit <Enter>
Type "disable mup"<Enter>
Type "exit"<Enter> to reboot

This disables Mup, but won't necessarily fix a boot issue.  I may hang at another point while attempting to load Windows.
BanacekPresident / CEOCommented:
Okay, I am experiencing the same problem in Win2000.  I took an old boot disk - actually it was Windows 95 - and got to a command prompt.  Via DOS commands, went into the C: Drive and went to \WINNT\SYSTEM32\DRIVERS and renamed MUP.SYS to OLDMUP.sys.  My system then booted up ok, but I no longer have mapped drives from my server.  So, it ain't over yet, but that is how I got back up.  My drives are formatted with DOS - just for this reason; I can get to the drive without NTFS up!  If you have NTFS formatted drives, find a dos like utility for them and you can probably rename and come up as well.

I will re-post when / if I get MUP.SYS to work again and bring back my drives!

I'm having the same problem with mup.sys although the issue started to occur when I imaged this machine. Any sugessions?
I have the same issue with a new install of XP.  It worked fine until I installed the driver updates for the Motherboard.  I then tried restarting using last known good and it worked fine.  Checking the drivers, I noted that the motherboard drivers for LAN, and USB were not set.  I reinstalled them again and the same problem recurred.  I will try again tonight using PS2 devices instead of USB and see what happens.  This seems to be the most likely answer considering what I have tried thus far.
There seems to be a pattern here. I am experiencing the same problem on an AMD 2600 machine with Windows XP Home.  I have tried the USB, reseating all cards, testing motherboard, and memory. All to no avail. The system worked fine for a month and a half after installation, then one day nothing. I could not boot to system, safe mode, or command prompt. I tried repair, and reinstall, but both aborted. I got an enigmatic message about corrupt files on the CD. Has anyone submitted this to Microsoft yet?
OK - I tried the USB thingy.  Reinstalled Mainboard drivers one at a time and rebooted successfully each time......until I installed the GIGARAID drivers.  This is when the whole thing came to a halt.

So I backed up again and left these drivers out.  Maybe they were dodgy, try downloading the Windows update and see what happens there.  Did this and then it died again.  This time I haven't installed the RAID drivers though.

You should note that I am actually rebuilding this PC.  Everything was working pretty well before, but I haven'thad a good clean up in a while so decided to rebuild.  The only thing I did differently was to separate my SATA RAID drives into individual drives (2 x 120GB).

So next step is to roll back and try a manual search for the specific updated RAID drivers from the manufacturer.  If this fails..........I'm installing LINUX!!

I don't have a RAID array. The install was done on a clean, new 120GB hard drive partitioned into 4 - 30 GB partitions.  I have run Norton Antivirus from CD and it says the drive is clean.

I think you may be right. LINUX may be the way to go.
Ok, there's a couple of similarities there.  

You - 120GB HDD partitioned in 4 x 30GB.
Me - 120GB HDD partitioned 30GB (SYS) and 90GB (DATA)

My previous install was on a 10GB Partition.  Is there an issue with the partitioning?

I am virus free as well using AVG 7.

Is your drive SATA or IDE?
For what its worth.  I just had the same problem.  I unplugged the USB Optical mouse and it booted fine.  Strange....
I think, what we can assume from all this is it has something to do with the hardware setup during install.  With mine, the USB made no difference although a couple of people reports that worked for them.  It is only during the configuration time after a driver upgrade that it is having trouble processing.

Another question, those of you having this problem, is it during a rebuild? or an initial build? or during an upgrade?  Did it just occur at random one day?

I will try going back to scratch.

Clear CMOS, Install system, Patch BIOS (@BIOS) and try again. That's my next guess anyway.

Hi this is prerak I have the solution for urs prob..
This error occurs because of an issue in Mup.sys, but the behavior only occurs if DFS Client is turned off. (By default, DFS Client is turned on in Windows 2000.) This error only occurs if DFS Client is manually turned off or if another program has turned DFS Client off..

Solution:-Method 1 – Use the Recovery Console
Start the computer by using the Recovery Console. For additional information about how to do this, click the following article number to view the article in the Microsoft Knowledge Base:
216417 HOW TO: Install the Windows Recovery Console

Open the SP4 uninstall folder. By default, the SP4 uninstall folder is in the following location:

Copy the Mup.sys file from the SP4 uninstall folder to the following folder:

Restart the computer.
Install the hotfix that is described in this article.
Restart the computer.
Method 2 – Use Registry Editor to Turn on DFS Client
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To turn on DFS Client by editing the registry, follow these steps:
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then click the following key in the registry:

Right-click the DisableDfs value, and then click Modify.
In the Value data box, type 0, and then click OK.
Quit Registry Editor.
The DisableDfs registry value uses the following settings:
DisableDFS: REG_DWORD: range: 0 or 1
0 = enabled; 1 = disabled
Default: 0

Make sure that the value is set to 0 to turn on DFS Client.

now u can enjoy
had the same issue at work,  it was an acpi enabled image on a none acpi compliant machine,  acpi is the advanced "new and improved version of Advanced Power Management" check your bois,
morrian's comment worked for me.  I had the PC just hang when it got to mup.sys.  So, while it is hanging and I'm debating what to do, I turned off my printer (usb connected) which incidentally, had a CF card plugged into it when my pc froze initially.  To make a long story short, the issue was directly related to the presence of a USB device that windows needed to clear in order to properly start.

happened to my dads computer.  was freeze on boot up and safe mode froze on mup.sys.  changed memory and booted right up.  working good as new.  woo hoo man!
i have 120 identical machines in the library here at this collage (of 840 systems) and amongst other troubles involving students, a month after a WinXP roll out, this one machine fails to boot.

not a problem, i have ghosted system images held on a server, and booted off of a USB key connected, wiped the main drive, and re-loaded the partition. twice. each time it is failing on "mup.sys". i'll have a look at that acpi bios stuff see if his makes any difference, but i have ghosted two other machines that are exactly the same, with no further problems. its just... ARGH! i don't need this! :)
sorted it. disabled booting from usb devices, enabled apci / acpi in the bios, and all is well. trouble is, windows doesn't like entering safe mode half way through the setup procedure. so stuck in a constant reboot error reboot cycle.

nothing a reimage won't sort.

thanks to whoever it was that suggested the acpi bios enabling thing.
Had a similar problem as some listed in this forum: WinXP would get to the boot screen, and then reboot a few seconds into it.  I couldn't boot into any safe mode (it hung at the mup.sys stage), and when I booted from a floppy or CD, I couldn't find my C:/ drive.  Did all the normal things...removing PCI cards, moving RAM, unplugging USB devices...nothing worked.

Finally, I resolved to reinstall, but rethought when, after I booted from the XP disk, I got a message that my machine was already in the process of upgrading (don't know why).  Tried the continue/finish upgrade, but that didn't work:  I got a blue screen with an unmountable_boot_volume message and some stop numbers.   Booted again from the XP disk, and chose the exit without installing/upgrading XP.  That worked....The normal reinstall files loaded from the CD, and I got to the expected install/repair setup selection screen.  I chose R to repair it, but at the DOS prompt, I typed in chkdsk /p and entered it.  It immediately started working hard on the first 50% of the drive and took a few minutes.  Got a message that it was checking more or recovering. AFter reaching the 50% mark, it moved fairly quickly.  When it finished, and returned to the DOS prompt, I typed in fixboot and entered it.   Then entered Yes (for was I sure?).  It worked a second and reported it recreated boot info successfully.  I exited, and it rebooted into XP like nothing had ever gone wrong.  

Hope this helps at least one or two of you.
That's funny. So many solutions for what apparently should be the same problem. Obviously MUP.SYS has nothing to do with this problem.

Here's what happenned in my case: I enabled the WiFi card on my Asus P5GD2 motherboard. I launched an Automatic Wizard thingy (not a Windws one, it was by Asus). It set it would autoconfigure the card. The application got stuck, though, wouldn't do a thing for 15 minutes. I rebooted and WinXP refused to boot.

I searched on EE, found this page, read all the comments, went into the BIOS, disabled the WiFi card and everything worked just fine. Except for the WiFi card of course. Hm...
I had similar problem. But wasn't any of those said above. I got the freeze up at mup.sys when booting Safe Mode. Freeze up, also when running Windows XP Pro SP2 Setup as soon as it says "Starting Windows" in the Blue setup screen. I tried booting from Floppy Disk; FREEZE UP! I tried flashing the BIOS with the Award "Update Bios" feature... as it tries to acces the bios flash file on a floppy, FREEZE UP !!! Tried everything above plus more, swapped hardware components... then I changed the processor and that was it !!! It worked after that !

The processor caused the system to Freeze up. When I put in another Processor It worked fine. I re-installed windows and system is running smooth since. So it was all because of a faulty processor. NB. This processor, an AMD XP 2400 was in this system for over 1 year and then all of a sudden, problems!

But this fixed my dilemma! Thanks all anywayz ! :)
Same problem here.. although MUP.SYS is definately not the cause.

2 brand new Dell Latitude D810's with the exact same symptoms. Note that they are identical in hardware. 1 freshly re-imaged. The other was imaged yesterday and a user profile set up without any issue. Today neither work.

A moment ago i went into the BIOS and changed the Boot order, and disabled Boot from USB Device. The first reboot it worked perfectly fine. I called a remote user to let them know as well, and rebooted the machine again for confirmation - NO GO!!!????!!! What gives? So now i have 2 laptops, identical, neither are configured to boot from USB, 1 of them i booted into Safe Mode and removed all USB drivers, but neither can log in.

I guess the next step is to involve Dell support and see if they can swap a CPU.
I have had this issue recur a number of times for different reasons. Accordingly, eachtime the solution has been different as well.

Windows XP is hardware reliant.  It registers hardware specific information when installed.  So if there is any change in the hardware, especially driver chips, motherboard or CPU, then it is likely to appear as this issue.

I recently fried a motherboard.  Couldn't get the same motherboard again so it was necessary to upgrade CPU and board.  I purchased a cheap micro board in the interim that suited my chip.  The microboard had a different northbridge.  MUP.SYS was where it froze.

When my new board and chip arrived, I coincidently had chosen a board with a similar northbridge as my fried board.  Installing MBoard and chip and turning the pc on everything worked fine.  Needed to upgrade all the board drivers, but XP had recognised enough of the architecture to boot up and allow me to fix.

Suffice to say that there is no single solution to this issue as MUP.SYS actually has nothing to do with the actual error.  It is simply a coincidence that after this file is loaded, a lot of the boot processing occurs.

Hardware is the answer.  Have you changed anything lately?  Is it significantly different from the superceded hardware?  Different Chip or manufacturer?

If you are imaging the PC, is it any different then the hardware on the master image?  Dell, and some other manufacturers, may not always use the exact same parts, even if it is the same model PC.  So don't make any assumptions.
KWH - Thanks for the post. In Dell's case, we purchased Latitude's because essentially they will use the same chips for 3 years before the machine is retired. However, i am forever skeptical about their manufacturing. We've recently changed from IBM to save $$$, and this is the semi-expected result unfortunately - inexplicable hardware issues.

We have 45 of these Latitudes in production, and aside from 1 remote and 2 local, no other hardware is showing these symptoms. But your post would explain why booting into Safe Mode and removing USB drivers, network drivers etc results in a single instance success, before the problem reoccurs.

The only reason i need to completely exhaust every avenue of failure BEFORE calling Dell is that their technical support is terrible. They have outsourced their call-centre to the subcontinent, and we're always faced with 20-questions before the call is escalated - enough to make a balding mans problems accelerated!
DAN - Good luck with Dell.  My experience has not been smooth one.  With smaller sites, I have typically purchased the componentry and built them myself.  At least this way I know what goes into them.  Outsourced Tech support, unfortunately, is firmly entrenched in this industry.  And the usual quality is not much better then an automated teleprompt system not unlike the Telstra directory assistance line.

I have had other consultants tell me it is easier to do a complete reinstall to recover from this failure as the time to diagnose and correct is often too great.  And in the majority of cases, that is exactly what I have done.

Like I said before....Good Luck.
Agree that the reinstall is the quickest form of recovery.. unfortunately home users aren't in the game for Ghost'ing machines. Into my 3rd day now, it now strongly appears to be ZoneLabs Integrity Agent taking offence with something in the system. I've got remote users on the West Coast (rural W.A.), and it appears that the ZoneLabs policy is sending their machines into a spin. While it's effectively preventing the O/S from loading correctly, i can't fix the issue (by uninstalling the software) until the remote users manage to log in successfully. For a bunch of farmers and vets it's extremely frustrating.

I think we've digressed from the actual topic here, but i think MUP.SYS gets a bad rap because it's last in line during the bootup phase in Safe Mode. Other similar problems can be caused by dodgy RAM, CPU's, USB and even network drivers... but ZoneLabs has me by the short and curlies at the moment..
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