I am trying to install the v1.3 patch for BG2:EE on Windows 7
I've downloaded the v1.3 patch from GOG. This creates the file patch_baldurs_gate2_enhanced_edition_2.0.1.2.exe.
After launching the exe, it indicates that it needs 80MB to update.
After clicking on OK, it starts update with a progress bar. The bar gets to ~1/8 then it is stuck.
The application (GOG Patcher / Setup) are shown as not responsive in the Task Manager (Applications tab)
The process (patch_baldurs_gate2...exe) is shown as consuming ~25% CPU cycles and 20MB memory
The longest I've let it run is 20+ min before shutting it down

I've now done this multiple times, and the result is always the same.

I have not installed any mods to the BG2:EE, and the only thing unusual for my installation might be that I picked a USB thumb drive (E:) to store the installation.

'cause the harddisk is almost full, and basically the thumb drive is just expanded storage. It's USB3 w/ 40+ GB free, so that's hardly the issue... But I will try to backup my saved games and see if a re-install onto the harddisk will allow the patch to work...

...
Well, that indeed solved the problem. I ended up uninstalling from the USB3 thumb drive, making space on normal HD, then reinstalling on the normal HD before patching, and it all worked.