Steam missing file privileges

On screen: An error occurred while updating [game] (missing file privileges)

This is a local permissions problem and has no relationship to Steam's service status.

What it actually means

Steam does not have permission to write into the library folder, or a file in it is locked by another process. It is a local permissions problem rather than anything to do with Valve's servers.

Common causes: NTFS permissions on the library folder, a read-only attribute, antivirus or Windows Controlled Folder Access holding the file, or a library on a drive that was moved between machines.

How to tell which one you have

Install the same game to a different drive or a newly created library folder. If that works, the permissions on the original folder are the problem. If it fails everywhere, it is your antivirus or the Steam service itself rather than any one folder.

Fixes, in the order worth trying

1. Use Valve's Repair Library Folder — Steam, Settings, Storage, select the drive, the three-dot menu, then Repair Folder. This is Valve's own tool for exactly this failure and it fixes the permissions case directly.
2. Clear the download cache
3. Add the Steam folders to your antivirus exclusions — Valve maintains a list of software known to interfere with Steam, which is worth checking against what you run.
4. Run Steam as administrator once — Diagnostic as much as a fix: if it works as administrator, you have confirmed permissions.
5. Remove the read-only attribute and check folder ownership — For the case where the library came from another machine or another Windows install.
6. Verify integrity of game files — After the write problem is solved, this repairs what the failed update left behind.

Operator documentation: help.steampowered.com. Valve does not document this error specifically. Their only relevant article covers update and installation issues generally, and says: the error results when Steam is not able to complete the installation, and the specific reason will be shown in the parenthesis at the end of the error message. They confirm the format and never explain the reasons. So anyone quoting an official Valve definition for the text in those brackets is quoting something that does not exist. Valve does separately publish the Repair Folder tool and a list of programs that interfere with Steam, both of which apply here.

Common questions