Hello and welcome to PixInsight Forum. These errors cannot be reproduced on our working and testing machines. No similar problems have been reported before, either.
This is a machine-specific issue. One possible cause is an antivirus application blocking normal access of PixInsight to its configuration settings file. Some file management applications running as background processes can also do things like these, as well as wrong or damaged system components. These problems don't happen under normal working conditions.
Please note that Windows 7 and 8.x are no longer supported officially by current 1.8.6 versions of PixInsight. I strongly recommend you upgrade your computer to Windows 10, performing a clean installation without vendor-provided utility software.
