We help IT Professionals succeed at work.

Check out our new AWS podcast with Certified Expert, Phil Phillips! Listen to "How to Execute a Seamless AWS Migration" on EE or on your favorite podcast platform. Listen Now


The Win16 Subsystem was unable to enter Protected Mode, DOSX.EXE must be in your AUTOEXEC.NT and present in your PATH.

usmcdevildog asked
Medium Priority
Last Modified: 2007-12-19
Every time I try to install certain programs like The Font Thing, MS Office extras, or other programs of the like, I get this message. I attmepted to replace the autoexec.nt, command.com, and dosx.exe files but that didn't help either. I checked the RAM using memtest86 (ran about 5 passes) and it checks out OK.

Did I miss something?
Watch Question

What is the message you are getting?  Are there any errors in event viewer from install attempts?

duh... ignore me.  damn reservists don't know how to read.
check this MS link on the same error

Make sure that the line, "device=%SystemRoot%\system32\himem.sys," exists in the CONFIG.NT file.

Make sure that the line, "lh %SystemRoot%\system32\dosx.exe," exists in the AUTOEXEC.NT file.

Expand HIMEM.SYS, DOSX.EXE, or both from the Windows NT setup disks or CD- ROM disc if either or both are missing from the SYSTEM32 directory.


My only experience with the win16 subsystem was that a poorly behaved application was eating up all the available GDI handles, which are not unlimited in XP.  Have a look in device manager and see if any such things are going on.  If so, the "fix" is to reduce the handlequota that you'll find in the registry from 10,000 to a lower number....I'm using 3000 and it's fine.


the comment from kabaam didn't work. that is pretty much what i had already tried before. i should add on a couple of things. OS is Win XP Pro SP1. I didn't have this problem prior to this last reformat (first one was factory, no problem; second one, no problem, reason for doing was too much garbage; third one (current), problem, reason for doing was i had installed the drivers in the wrong order in the second one which created problems requireing a 3rd reformat).

I looked in device manager and i couldn't find the gdi handles and there is no such thing as handlequota in my registry. Or did I miss something?


however i did do the suggestion from kabaam. With the same result as before.

try this one here
it includes some other line entries that are required


Those are all correct. The MS Office Add-ons I was refering to are from Office 2003. I don't know if they fit in under the 16-bit program category or not.

Agh....sorry.  I said "device manager", of course I meant "task manager".....what you get when you hit ctl-alt-del.  In task manager, the parameter is called GDI Objects.  Tha parameter I set to 3000 in the registry is called GDIProcessHandleQuota


Nothing. The only registry entry that came close was called gdi32 with a value of gdi32.dll No mention of gdi in the task manager either.

I'm very surprised that there's no entry called GDIProcessHandleQuota in your registry.  It's pretty fundamental.  As far as task manager, you're going to have to add some columns to your view on the processes sheet.  There's a world of information there, too much in fact.

If you can't find the dword entry in the registry... that may be the problem.
I am not familiar with GDI precesses but this is where it would be in the registry.  I found it in mine with a value of 10000
 HKEY_LOCAL_MACHINE/Software/Microsoft/Windows NT/CurrentVersion/Windows


Ok, found the string in the registry and changed the value to 3000. Did a restart and still the same issue. Don't know why I didn't find the registry entry earlier, but the search didn't bring anything up using various different keywords (I wasn't inclined to go through each entry!).

ok... one question on the entry that is important.
when you change it to 3000 ... was that decimal or hexidecimal format?  It makes a big difference
Stand recommends using a LOWER number such as 3000.  in hex 3000 is larger than 12,000 decimal.
when viewing via regedit .. the number in ( ) is the decimal value.   the numbers preceding it are hex.
if you changed it to 3000 it should look something like    0000bb8(3000)


Yes, I did do the change in the decimal format, not the hexidecimal format. I know JUST enough about it to understand the difference.
Unlock this solution with a free trial preview.
(No credit card required)
Get Preview

try the first one first... I think it is closer to your problem

I am experiencing the same problem as usmcdevildog.  I printed out the Microsoft support solutions listed by kabaam, 222975 and 168925, but unfortunately, the instructions to correct the problem are too difficult for me to understand.  I thought I was pretty good at computers, but I just don't understand the instructions.  Any suggestions?

Does anyone know if PCDoctor will fix this error?


well, to be quite honest with you, I think your best option would be to "repair the OS" not reinstall but just repair. That way, you do not need to reload all your software documents etc.

However, I would make a backup just in case it doesn't go right and you have to reinstall the OS anyway. I had it happen once to me, when I had SP2 Beta for WinXP Pro installed.

The repair solved the problem for me once and for all, the Microsoft seuggestions only work part of the time.

Hope this helps.
I have the same issue - the only difference is... I have 40 computers with this problem. Win2000 SP4.


I have only been able to fix the problem with a reinstall or repair (cannot be done with XP if it was upgraded to SP2 via internet or update disc). However, I have noticed that certain other problems I've had, can be solved by deleting the user profile and then recreating it. I haven't tried it on this problem yet, but it may work. Also, are you running specialty programs such as Maya, AutoCAD, 3D Studio Max, etc. They may cause problems as well.
I received  this same error, "Win16 subsystem unable to enter Protected Mode," trying to run a 16-bit app in Windows XP SP2.  Googled and looked at a lot of threads, verified the existence of Autoexec.nt and Config.nt, verified proper configuration, verified the existence of mscdexnt.exe, redire.exe, and dosx.exe.  Tried the RAM configuration in Config.nt.  Another symptom I noticed is "file not found" 3 times when typing "command" at the XP command prompt (CMD).

I tried "dir C:\Windows\System32\dosx.exe" at the CMD line, and got "file not found."  So I changed the attributes of the dosx.exe file, removing the S (system) and H (hidden) attributes.  I typed "command" at the CMD line, and did NOT get "file not found."  I changed the same attributes on redir.exe and mscdexnt.exe.  Then, I tried running my 16-bit app, and it ran successfully!
Unlock the solution to this question.
Thanks for using Experts Exchange.

Please provide your email to receive a free trial preview!

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.