Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win


Missing network drives

Posted on 2003-12-02
Medium Priority
Last Modified: 2012-06-22
I am seeing the following :

15,000 XP Clients, Win2k AD backend.
Intermitantly, drive mappings dissapear as follows
Not visible in My Computer
Still visible in Explorer but drive name is corrupt and file type identified as raw
Still visible at cmd prompt.
Killing and restarting explorer.exe resolves issue.

We have a MS Premier contract but MS and ourselves are struggling to replicate this issue.
Has anyone else seen this issue? Better still, fixed it? I am after an explicit answer - simply deploying XP SP1 is not viable.

500 points to someone with the answer.....

Question by:sweatbeast
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 14

Expert Comment

ID: 9863303
Have you tried another brand of ether card in the win2K machine?
Is the mobo up-2-speed on the chip updates?
LVL 41

Expert Comment

ID: 9863732
Help me understand the problem...

You've got 15,000 clients that are all experiencing a problem with dissappearing drive mapping?   Are they all mapped to the same server (or does the target resource not have a bearing on the problem).   Are they all in the same domain... same OU, etc

I presume this is a Win2k "native mode" domain where network resources are "advertised" in Active Directory as well as available for the picking thru the Network Neighborhood/My Network Places?

How are these mapped drive created?  A login batch?.. by hand, by application?... is the "persistent" flag set?

Why are you using mapped drive letters at all?  If all your clients are WinXP, why not use UNC path's instead (just curious)

Expert Comment

ID: 9864211
There is a reg setting that tells the servers to disconnect clients after n minutes of inactivity. I think by default it is set to 15 minutes but the setting is in seconds so 900 seconds. Last time I looked at this, there was a ceiling to the time you can set. The alternate option was to set to -1 which was unlimited, but then all of the dynamic server setting adjustments that Windows can perform gets set statically. While I've typically seen the red X symptom, if the drive mappings aren't persistent, I'm wondering if they just wouldn't get removed.

Check this article out. If it's not the answer, let me know if you do figure this out.


Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

LVL 13

Expert Comment

ID: 9866678
The problem with disappearing and reappearing resources such as drive mapping can occur during the process of master browser election.  During this period service ceased to broadcast.  If you have a dual-home (two NICs) server - see my previous responses on this issue below.

If you don't have a dual-home server, check to see why your networking is forcing a master browser relection.  Is the network traffic too heavy?  Is the server too busy?  Is there a faulty cable or NIC in the server?  How many server do you have that you forgot to accounted for ie... Exchange, etc???


Here are my previous posts: ********************
Your problem is in dual-home server.  It's a known problem - what's happening is the master browser election taking place and causing the network resources to disappear so clients are not able to access the resources until the election is complete and the client can see the resource again.  (Added) Meanwhile, the clients have to wait.... so network appears a very slow........ It takes minutes to logon and minutes to access anything.....

Here are my previous answers to the problem:


Here is the MS knowledge base article and how to deal with it:


Author Comment

ID: 9874756
Thanks all for responses.

Let me clarify - the drive mapping is still available via command line. It is available within windows explorer but the label is corrupt and the filesystem is identified as RAW. From My Computer it is not available.

Networking itself is not dropping out - connectivity via a UNC to the same host is fine. However, interestingly, file copy results in an error stating that the target does not suppot long file names, so you have to shorten to 8.3 format.
Killing and restarting Explorer.exe fixes the problem.
This occurs to random users at random times.

Expert Comment

ID: 9997330
And what about the event logs?
LVL 13

Expert Comment

ID: 10000746
Killing and restarting on the host or server side?
Try to replace the NIC on the server and possibly the protocol stack.....


Author Comment

ID: 10003641
No entries written to Event log on client or server.
Network drives hosted on several different servers; not server specific.
LVL 13

Expert Comment

ID: 10004071
Check for a common router/switch/bridge that these workstations are using.  One of them may have bad memory corrupting packets....

LVL 13

Expert Comment

ID: 10077546

How is it going?

cheers / Gnart

Author Comment

ID: 10154814
This is happening enterprise wide, utilising many different routes with no common denominator on the network side.

Expert Comment

ID: 10155761
I too have this issue. Red X condition on mapped drives but UNC path through explorer works. I found some info indicating that it may be DNS related so I bounced my internal AD integrated DNS server and the drives came back. I do occasionally see  browser election issues but I'm not sure that is the issue.

LVL 13

Expert Comment

ID: 10195918

Adding on th brianperry's post.  Install network monitor on the machine that usually exihits the problem.  WHen the problem occurs, try to access through the problem and look at the traffic log.  Then, access through the \\UNC and compare the traffic log... to see if its a DNS/WINS issue.


Expert Comment

ID: 10880498
I have a client with the same issue.
In explorer some network drive letters are missing or the name is corrupt.
The drives can be accessed from the run or command prompts.
A simple NET USE from the command prompt will show all the drives are mapped properly.

This is the information I have found so far:
Microsoft "Drive Letters of Mapped Network Drives Are Missing in Windows Explorer"
Has a patch you have to contact MS for. (Should be free though)

Another suggestion is that the machines may have TweakUI on them which can hide drive letters.  This may be a bug in it as the article doesn't suggest you can fix it, but simply remove it if installed.  TweakUI is a MS PowerToy/Tool.

Finally,  there is another possiblility.  Does your company use and spyware to monitor employees?  If so this also may be the culprit as some of them have the ability to hide drive letters and may cause this type of error.

Let me know if any of this succeeds.

Good luck.

Accepted Solution

Computer101 earned 0 total points
ID: 12375713
PAQed - no points refunded (of 500)

E-E Admin

Expert Comment

ID: 13614547
Greetings sweatbeast and All,

I to am having the same issue. It is site wide with 1,200 users.

The issue maifested itself after we made two changes. Cicso Router and Switch upgrades and IP Scheme Changes.

Here are the IP schemes:

192.168.50.x = Server Subnet
192.168.51.x = Client Subnet
192.168.52.x = Client Subnet
192.168.53.x = Client Subnet
192.168.54.x = Training Subnet

* All workstations are Win2k Pro
** All Servers are Win2k Server and Win2k3 Enterprise.

Symptoms are Mannped Drives Randomly disconnect and hourly Master Browser elections from workstations from different subnets.

Temporary Workaround:

I can turn off Browsing on the workstations that are calling for elctions in the AD2k3 domain controllers and is resolves the issue until more workstations start up the elections. If I let it go for 2 days, we start all over with Mapped Drives Disconnects.

WINS and DNS services are working perfect with no events issues in the WINS and DNS servers.


Featured Post

Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Just about everyone has an old PC laying around.  Ask anyone in the IT industry, whether they are a professional or play in it as a hobby.  From outdated Desktops to cheap "throwaway" laptops, they are all around and not as hard to "fix up" as you m…
Sometimes a user will call me frantically, explaining that something has gone wrong and they have tried everything (read - they have messed it up more and now need someone to clean up) and it still does no good, can I help them?!  Usually the standa…
This is used to tweak the memory usage for your computer, it is used for servers more so than workstations but just be careful editing registry settings as it may cause irreversible results. I hold no responsibility for anything you do to the regist…
Hi friends,  in this video  I'll show you how new windows 10 user can learn the using of windows 10. Thank you.

596 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question