I once had a fresh installation of Win7 on an SSD drive. Bearing in mind what you always hear about write cycles on these things, first thing I did was changing the TEMP/TMP variables of SYSTEM and my user to a second drive, which path would be D:\Temp_Win (folder name due to some dodgy installers and programs like to mess with TEMP directories in root folders).

My userprofile is a member of the administrators-group and UAC is turned off. There are also no firewall(s) or anti-virii/adware applications installed.

This worked fine up to SOME point in time which I cannot pinpoint. I just recently noticed that the USER variable of TEMP and TMP don't point anymore to the folder I had set, because I went to change my path variable and saw it.

Now if I try to change back TMP and TEMP set for the user (no matter if I use the corresponding sys config panel or by editing the registry-path HKCU/Environment/TMP & TEMP), Win7 (or SOMETHING) keeps resetting both back to %USERPROFILE%\AppData\Local\Temp

I CAN change the value, and its starting to be used as long as I don't log off because I see files popping up in my custom directory. So it doesn't seem to be a permission issue in the registry. I can also kill the explorer.exe and restart it via taskmanager, and my custom temp folder is still in use. But as soon if I restart or log off and back on, the user-variables are back to %USERPROFILE%\AppData\Local\Temp just as if something is writing this back.

Changing the temp path and immediately (re-)booting into safe-mode with the exact same user does NOT reset the temp values so it seems like its something I installed on the profile.

Note that the affected system has no network connection at all, and a malware-check with live-cds from Avira and Sophos have found that machine to be clean.

Is there something that could help tracing this down to either the system or to some installed application?

~~~~~~ I saw this question TEMP environment variable occasionally set incorrectly but it doesn't seem to be related to my problem. Doctor google turns up nothing about the above described behaviour.

3 Answers 3


What you experience sounds like a corrupt user profile, where windows is unable to update your profile after you log off. Is your computer part of a domain where your profile is stored? (because that would require a different way to reset your profile, and to test other things)

If not, can you create a second user, make the registry changes, restart, and test if it remembers it?

EDIT based on the comment below:

It seems you're setting the temp and tmp settings wrong. Try setting it using the following method:

1. Go to Start Menu
2. Right click "Computer"
3. Select Properties
4. On the left, select the 4th option: Advanced System Settings
5. In the tab Advanced, at the bottom, press Environment Variables...
6. Here you have the variables for both your user and system defaults. 
   Change at both locations.
7. Press Ok and OK.

You shouldn't need to reboot for the effects to set, but you should reboot to see if they are kept.

  • No, its not part of a domain. I created a second user. It does remember when I change the temp variable. I further tried to change my own PATH variable (that is on the seemingly corrupt profile) and it is also remembered during a reboot. So it seems only the TEMP/TMP variables are affected.
    – user314206
    Apr 9, 2014 at 12:36
  • @user314206 I've added a 2nd answer.
    – LPChip
    Apr 9, 2014 at 12:43
  • Based on your edit: I did exact that and the change is reflected e.g. when I open a command prompt and enter cd %temp% it takes me to my custom temp folder. After a restart, my change is gone. Also please note that the change IS remembered when I don't boot normally but boot into safe-mode after the change. Only a normal boot resets it back.
    – user314206
    Apr 9, 2014 at 12:56

Honestly, you should NOT remove temp folders, pagefile etc from your SSD.

Your system will feel and run better by having them on a SSD as opposed to a HDD (temp files is actually the best example of where a SSD shines compared to a HDD - lots of random writes/reads and often tiny files, on a HDD that is slow and creates a lot of fragmentation).

The write cycles issue on SSD is blown absolutely out of proportion. My SSD has been running 24/7 for 3 years now (with Win 7, pagefile, temp folders etc) and it only lost 3(!)% of its shape. Bear in mind that it is one of those SSDs with relatively few write cycles (Intel SSD 320 40gb) so most drives would have lost even less than that in 3 years of 24/7 usage. I'm also a power user, and I certainly do a lot of writes (plus my SSD is usually 60-75% full) compared to your average joe.

You can read up about it on the internet, tests have been done where they were hammering the SSDs in a way that is unrealistic for virtually every user out there and they still failed to "kill" the drive (you can only kill the write capability, mind you) in less than years.

So IMO, just don't bother.

  • I read much about this exaggerated myth of wearing out SSDs and your comment nearly did the last bit to convince me to just handle it like a normal HDD. However my main problem remains. Someone suggested msconfig to me to disable all startup programs one by one to test which application might mess with that variable. Will test that this evening.
    – user314206
    Apr 11, 2014 at 12:54

Sorry for gravedigging but I found out the culprit. It was Archicrypt Ultimate Ramdisk. It has a feature that messes with the temp variables (to move temp files to a ramdisk etc) and I had it set up incorrectly. Need to tick "redirection of temporary files is done manually" in settings tab if you don't use that feature.

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