As per title, I encountered this problem

- got a BSOD playing
- at restart, rerun the app, opening save game got into loop
- GoG Galaxy says it failed an update (E9)
- I unistall the game
- Cannot re-install (E9 error)

I have the same problem trying to download/update the game. Since the devs pushed out a new update today (1.1.1), I'm assuming the problem lies with the new build. I've notified GOG via the support system, but it might help if multiple people report this issue.

That being said, you should still be able to download the offline installer for 1.0, so you could manually install the game and play on 1.0 until this problem has been dealt with.

I just wanted to put this out there.

I will attempt tomorrow, hoping that my save was not lost/corrupted

I'm inclined to believe the BSOD is specific to OP, and the save corruption is likely linked, possibly with the BSOD happening at an autosave.

The E9 server error feels like it should be its own thread though, as between it showing up on fresh installs, updates, and across multiple machines and accounts, it seems like a misconfigured version was put up to the Galaxy servers on the devs end. I've seen this a few times on itch.io, but I've never personally seen it happen on any other distrobution platform until now.

Edit: I have not experianced any save corruption, and cloud save sync seems to be working correctly for me. Partially the reason I sugested the save issue was Original Poster specific

same here, keep receiving the same E9 error message when trying to re install the game,

Looks like they pushed a hotfix and the game can be installed again.

I contacted GOG Support yesterday regarding the E9 error, apparently it was something specific to Galaxy: the game could still be installed via downloading the offline installer off of our GOG's web page library. That has been fixed, the game can now be installed/updated via Galaxy with no issues whatsoever.

As for the BSOD and save corruption issues, I didn't get whether that was a previous version or a patched one problem, considering the OP wasn't being able to install it, I'm assuming it happened with the 1.0 version, not the new 1.1.1 one. Still, I haven't tried the patched game yet, but I never came across any issues with the previous version. I'll go check it out as soon as possible, hopefully everything is working just fine.

[EDIT] Tried the 1.1.1 patched version, everything is smooth as butter, it does still recognize my previous save/progress, no BSOD, no nothing. Mind you, I'm running the game on a Huawei Matebook D14 (AMD Ryzen version) laptop that's supposedly way below minimum specs and it still manages to run Death's Door on 720p with every graphical effect/improvement turned on with no slowdown at all.

I don't think this was strictly a GOG Galaxy issue. Yes, you could still download the offline installer, but that installer was still version 1.0. I'm pretty sure the issue was with the build provided by the devs, since it started with the release of 1.1.1 yesterday and it got fixed with the release of 1.1.1-h today. But hey, they fixed it very quickly, so this is a purely academic point now.

Speaking of BSOD and save game corruption, I have seen one or two people on the Steam forums claim they couldn't access their savegames after updating to 1.1.1. I've tried it on my end and I still have my savegame. I think someone in the Steam forum also mentioned the current build of the game crashing after a few seconds in the main menu, though I can't confirm that on my end either. Just be aware that a small number of people are still encountering issues with crashes and savegame loss.

Another piece of information which might be of interest to the discussion: With the latest patch, Death's Door should now create a savegame backup every time the game saves. So in the future, it should be possible to revert to the backup file if you somehow get your main save corrupted.