My temp directory is filled with python envs, until the disk is full. I strongly suspect axiom Boinc tasks, as they use python and I had no problems before runnng axiom.
As someone noticed the same ?

Note : running CPU and GPU tasks on Windows 11.

In reply to dthonon's message of 12 Feb 2026:

My temp directory is filled with python envs, until the disk is full. I strongly suspect axiom Boinc tasks, as they use python and I had no problems before runnng axiom.
As someone noticed the same ?

Note : running CPU and GPU tasks on Windows 11.

Yup I did too, I used a small program to delete them all, which is how I found out what they are. CCCleaner was the program and it took awhile to do it.

I noticed a sharp drop in free disk space and went looking for the cause.

I found the cause in the directory: C:\Users\{Name}\Appdata\Local\Temp ( on Windows10)

Every time you recieve a Axiom WU it creates a directory with the name: -MEIxxxxxx (xxxxxx = a number) and it is huge.
The project does not do a cleanup after the WU is finished.

But the directory and its contents should not be there in the first place. Temporary data for a WU should be put in the Boinc Slot diretory when the WU is running so that it gets deleted when the WU is done.

Everybody keep a close eye on this because until the Admin changes this you will need to delete those file in the Temp directory by hand or else your disk will fill up.

This is fixed in v6.08 (deploying now).

The _MEI* directories in your Temp folder are from PyInstaller's --onefile mode. The binary extracts itself to a temp folder each run and cleans up on exit, but if a task crashes or gets killed by BOINC, the extraction directory is left behind (~27MB for CPU tasks, ~1.1GB for GPU tasks).

v6.08 now detects and removes stale Axiom _MEI directories on every task startup. It checks each _MEI folder for Axiom-specific files before deleting, so it will not touch other applications. Only directories older than 2 hours are removed.

In the meantime, you can safely delete any _MEI* folders in your Temp directory that are not currently in use.

Sorry about the inconvenience — this should have been handled from the start.

And yet it filled my HDD up yet again today OUTSIDE of the designated BOINC data directory. This is not acceptable.

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Sorry to hear it is still happening. v6.09 (the current version) changed PyInstaller to extract into the BOINC slot directory instead of %TEMP%, so new _MEI folders should no longer appear in your Temp folder at all.

Could you check which app version you are running? In BOINC Manager, look at the Tasks tab — the application column should say v6.09. If you are still on v6.08 or older, try updating the project (Advanced > Update Project) to get the latest binary.

If you are already on v6.09 and still seeing new _MEI directories in %TEMP%, please let me know and I will investigate further. In the meantime, the old leftover _MEI folders from previous versions are safe to delete.

Second time in few weeks I tried running this project. As well as aborting ~14hrs of running tasks, it has filled up my HDD again. Same place as before C:\Users\{Name}\Appdata\Local\Temp.

Windows 10, 3700X cpu

Sorry about that. The directories in your Temp folder are leftover from older app versions. This was caused by a build prompt I was using that didn't include the correct extraction directory flag — so multiple versions went out without it. v6.35+ now extracts into the BOINC slot directory instead of %TEMP%, so no new _MEI folders will appear in your Temp folder.

Additionally, the client now includes a built-in cleanup that detects and removes old stale _MEI directories from previous versions on every task startup. If you let a v6.35+ task run to completion, it should clean up the old leftovers for you automatically.

In the meantime, you can safely delete all _MEI* folders in C:Users{Name}AppDataLocalTemp — they are not needed by any running tasks on v6.35+.

To confirm you are on the latest version: in BOINC Manager, check the Tasks tab — the application column should show v6.35 or higher. If it shows an older version, try Advanced > Update Project.

Apologies again for the trouble — this should now be fully resolved.