I was helping a user who was not able to run certain functionality, and in the end it boiled down to failure to access the temp folder. This was with the latest nightly.

Should there be some extra check added to tell users if permissions are incompatible? Otherwise, it is not possible to figure this out without looking at the log, and beginner users will never think to look into it. In this particular case, the manifestation of the problem was failure to load a DICOM series with a plugin that did conversion and needed access to temp folder.