Hi,
Seeing as your issue depends on the computer environment, it would help if you could post more information about this environment (e.g. OS, filesystem) (and in particular the differences compared to where it does work). When you use System Monitor / Task Manager, do you see anything out of the ordinary (e.g. 100% disk usage)?
You should also post (the relevant part of) this code, ideally condensed down to a MWE. See also Please read: make it easier to help you (4. and 5.).