It's never OK to delete temp files when the files are still open.
The temp files should be deleted by the application itself as soon as you close the files.
Why they are not being deleted is the problem you need to troubleshoot. As a Mac user I can't tell you how to go about doing that on a Windows box.
As Station_Two points out, the TMP files should be deleted, when you exit Ps. However, every now and then, I find that a few did not get cleaned out.
If the Ps editing session is over, and Ps is closed fully, then you can delete those files. Check their dates/times to get a better handle on when they were created, as knowing that info, might be helpful in troubleshooting.
- Is that destination drive internal, or external?
- What is the connection type, such as SATA III internal, or USB 2.0 external, etc.?
- Any program crashes on Exit?
- Any power failures during Exit?
You must be responding by the dreadful email method as there is nothing in your reply.