How to fix Failed to Open Descriptor File Error [Solved]

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how to fix failed to open descriptor file error

You fire up a game you want to play with your friends, excited to jump in, and instead, you get the dreaded “Failed to Open Descriptor File” error message that hits harder than a headshot from a distance.

If you’ve played ARK: Survival Evolved or Survival Ascended, Fortnite, Valorant, PUBG, or Palworld, you’ve probably seen it. The error has even crept into Friday the 13th: The Game, Gears of War 4, Icarus, and A Way Out. Basically, if it runs on Unreal Engine and has a multiplayer element to it, this error will likely pop up.

So what’s happening? The game can’t open its .uproject (or equivalent descriptor) file – the bit that tells the engine what to load and where. The exact file name changes per game, but the error message always looks similar to what you can see below:

failed to open descriptor file
Example of the error message I’m getting

But no matter what game you’re playing, if you are getting the Failed to Open Descriptor File error message, the fixes recommended below will work. Most likely, the first fix I share is all you need to know.

1. Verify the integrity of the game files

This is the most likely fix for the problem. Simply check the integrity of the game files, let the installer update any corrupted files, and your game will work like a charm.

In order to verify the integrity of the files do this:

  • Right click your game in your Steam Library and select Properties.
  • In the new window, click Local Files and then “Verify integrity of game files.”
verify file integrity

And this is it! In 90% of the cases, this will solve your problem and you won’t see the Failed to Open Descriptor file error message.

2. Uninstall game, clear the cache, reinstall

If verifying the integrity of the local files won’t do the trick, you might have to uninstall the game, completely clear the file cache from your system and install it once more.

In order to do this, first uninstall the game from your system. (Right click it in your library -> Manage -> Uninstall).

Next, launch your Steam client and click on Steam -> Settings in the top bar.

In the new window, click on “Downloads” and then the “Clear download cache button” as seen below:

clean download cache

Confirm the action, log back in to Steam and reinstall your game. You should no longer receive the “Failed to open descriptor file” message.

3. Move the game files to your System Drive

Some users have reported that simply installing their game on their system drive (where Windows is installed, usually C:\) fixes the problem.

Simply moving the game files manually won’t do the trick, so you will have to do this instead:

  • In your Steam client, click Steam -> Settings -> Downloads.
  • Click the “Steam Library Folders” and under “Storage Manager” click the + button to add your System Drive (if it’s not already there).
  • After adding it, scroll to the game you’re getting an error from, select it and then click the “Move” button.
add new steam library folder

This will move all the game’s files in the System Drive. You might want to check their integrity once more before launching, too.

This will ensure that even if some files got corrupted during the move, they will not cause any problems.

4. Advanced Fixes (If Nothing Else Works)

Normally, the fixes recommended above will make this annoying error disappear. But if you’re still dealing with it, there are some more advanced fixes you can try.

Try these one by one, in order from top to bottom:

  • Check the install drive path. Make sure the install isn’t on a network share or a drive that changed letters. Reinstall locally if needed.
  • Check file/folder permissions. The game folder should have read/write enabled.
  • Disable antivirus temporarily. Some security tools block Unreal files so either add it as an exception or disable it while you play.
  • Repair Visual C++ Redistributables and .NET Framework. Broken dependencies can trigger the same descriptor error.
  • Restore or re-create the .uproject file. Mods or dev builds might delete or rename it accidentally.
  • Check drive health and free space. If your SSD is full or throwing errors, fix that first.
  • Wait for the next patch. Occasionally, this bug is on the dev side. Players have reported it appearing right after game updates, then disappearing after a hotfix. So if nothing else works, waiting is the only thing that you should do.

If you somehow manage to find a different thing that fixes this problem, don’t hesitate to let us all know by commenting below – make sure to also include the game that’s giving you this error.

Calin Ciabai
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