So I started downloading 3 games at one time and walked away. When I had returned, one completed successfully and the other 2 failed with the error above and "Disk access error occurred during installation." Tried relaunching Galaxy as admin as I had found in another post but it did not help. Also tried lowering UAC settings all the way down but still getting the same error. I haven't tried any other games yet.

Any ideas on this?

I have the same problem E4

I have the same with Witcher 3. It fails on 95%.
And I also can't change 'Game installation folder' in settings (i supposed it would resolve the issue), after selecting new folder new value isn't set up.

Bump, any ideas on this one? Everything keeps failing.

To be in the safe side try to make antivirus exceptions for the Galaxy and the gog games (if not the same) folders. Probably It is not the reason but could be worth the try.

extra info besides issue confirmation :

1. GOG Galaxy 2.0 worked earlier in my D: drive, but stopped working and I had to uninstall and when trying to reinstall it didn't work anymore. I had to resort to installing in the default install path which doesn't have enough space for all my GOG games

2. Can't change game installation folder, I select a new folder and it keeps trying to install to the default c: drive folder

3. It installs up to 95% and then the resulting above mentioned error "Installation Failed {E4}"

4. The above mentioned method of running Galaxy 2.0 as admin - didn't work

5. Added both the galaxy app folder and default games folder to Windows Defender's exception list (I have no other anti-virus software) - this doesn't work either

6. This appears to be an issue with only GOG games

.
.
This is clearly a bug in the client, most likely triggered when you try the "Import folder" feature to add existing games folders instead of downloading it

Work-around for GOG games only:
exit the client completely, log on to the GOG website, download the offline direct installer for the game
when installing do not take the option to use the Galaxy/GOG app
after the game is fully installed and launched for the 1st time it should show up in the Galaxy 2.0 client after that

Note: GOG should fix this otherwise the launcher is pretty much pointless when this error is encountered, since it should be 100% capable of servicing GOG products. Prior tickets about this issue and the other issues in Numbers# 1 - 6 have also not been addressed. If GOG no longer has any interest in addressing these issues despite repeated support tickets and forums posts by the community then we should declare that the Galaxy 2.0 app and the older app which cannot function after 2.0 is installed or uninstalled, is then useless as a concept and only offline installers should be used. This will result in GOG sales decline and player base decline

Solution : FIX THE CLIENT! Pay attention to your support tickets and forum posts GOG!

EDIT : found this post on reddit with a possible fix but at this stage until GOG decides to properly fix their client I'll stick to my original workaround to install GOG games in the folder of my choosing. Can't be bothered anymore to fix something that just repeatedly gives problems with no clear indication of GOG support staff actually interested in user feedback or support tickets For link please see the screenshot since it seems that this forum doesn't even allow me to post links that can fix their mess of a launcher.

Same issues and more ! E3, E4, E10...
So freaking annoying: why did you push the open beta on us and phase out the previous version ? I can't even install games anymore, I tried to uninstall GOG but now I can't even reinstall it because you didn't provide a fucking direct link to the client.
What is the point of having this web based installer to download the real installer which fails every time stating that GOG servers are unreachable ?
It fails randomly at different stages of the 228mb download !
And absolutely no news since December, and no patch to the 2.0 beta...
Terrible !

SOLVED: Must unistall and delete all traces of GOG from PC.

Then reinstall from website.

There was an update that evidently GOG would not download automatically. Hope this helps.

~DeBarbarian

Hi,

I have the same problem. But for me it started when I denied UAC access rights for "Master of Magic" Update.
Now every update and install fails...

Agreed that this browser is garbage, It used to work. I haven't used in months, but when I tried last night, I'm having the E3 error is when trying to download, "retry" does nothing, I can't sync other platforms, can't get game info or friend info, etc.

I've checked all the fixes apart from a complete uninstall and removal, which I'm about to do. But let's face it... that's a ridiculous step to have to take. I'm not sure what happened along the way, but this browser was fine, once upon a time. If the reinstall doesn't work, I doubt I'll bother with it again and just use the website.

"Officially" they are "4 weeks" behind on support tickets. They seem to have only realised that providing some kind of estimated timeframe is important sometime within the past 3 weeks though, since I have a ticket almost a month old which is still yet to see a reply and which came with no estimate of how long a wait I was going to have.

In reality, they're almost 3 months behind on support tickets. I also have a ticket from March that's still yet to be replied to.

In the middle of what appears to be a near-total (if not actually total) shutdown of support for their platform was... MAYBE not the smartest time to be forcing a beta build of their client onto customers in direct violation of our opt OUT of beta testing settings...

Faced with error “E4” when updating “Master Of Magic” in Arch Linux (I run client through Lutris), I solved the problem in the following way: for directory with gog games and for all subdirectories set access rights as 777.

Just in case, you never know.

(online translated)