Hi Shadow, welcome.
I don't work with any UAC-using OS, but let's try to solve this.
Under normal circumstances due the UAC you have no write access to "..\Program Files\.."
You have updated from 8.80.0300.
HOW did you did this? With the portable archive or with the actual installer?
Since 8.80.0314 the installer prompts you on upgrade to agree
to move the XYplorer data folder to an folder where you have write access, did you agree?
Your current XYplorer.ini should be in that "user\username\AppData\Roaming\xyplorer" folder.
AppData_Roaming_XY_001_c100.png
What is the content of your XY startup.ini?
The size of your ini is 18 byte only, but should be 34 if it would contain the following standard:
[Appdata]
Path=%appdata%\XYplorer
which points to that roaming folder.
Note that this folder may be hidden, as well as the file extensions (as .ini)
To make them visible, press ALT-key and go to "extras > folder options" > "View"
Win7_show-FileTypes_and_Hidden-Folders001_c100.png
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As an alternative setup, to leave all data-files inside the xyplorer folder,
you can give "Modify" rights for "Users" to the "...\program files\xyplorer\" -folder:
W7_ModifyRights_for_Users_001_c100.png
In that situation you doesn't need the startup.ini at all. Simple rename it to startup.txt.