Hi all,
set t sends :
TEMP=C:\user_name\AppData\Local\Temp
TMP=C:\user_name\AppData\Local\Temp
Ok. Strange that the 4 line batch file didn't help, since it should have redefined those variables without spaces.
Your workaround setting it to the Octave folder could get messy. Usually best to make a separate folder nothing else is using. Maybe just make a simple C:\Octave\temp folder and set it to that. The bug report mentioned earlier has a fix already in place for this. You can check it out or just use your workaround until the next octave release.