Unable to launch latest save, was informed sister DLC was not installed.

Uninstalling and reinstalling sister dlc did not fix problem, dlc is still missing.

Uninstalling base game results in failure, local copy of the game is corrupted.

I think the sister dlc is bugged or corrupted, i am unable to un-select sister dlc when installing

tldr; cant reinstall game

I had the same problem. Its something wrong with the latest patch.
I rolled back to the previous one and it started working again.
Was pretty easy using GOG by going to the game config menu and turning off auto updates.
Then clicking on version 1.11.00.00.

My problem is i cant disable the dlc OR the latest patches pior to install

and the install is corrupted every time i try

but, honestly, thanxs for the reply

I have the same problem. I bought a faction, but it cannot be selected in the game. Not even on the list.

I found a workaround. I downloaded all the installers from my library and installed them all manually, that worked for me. I didn't bother with any of the patches, just the DLCs.