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Disk Read or Write Error

When installing or updating a game, Steam displays an error message:

  • "An error occurred while updating [game title]"
  • "An error occurred while installing [game title]"

Either of these messages contains the following detail in parentheses: "disk read error" or "disk write error."


The main cause of this error is generally errors on your hard drive. These can either be bad sectors that have not yet been marked as bad by the filesystem, or your hard drive may be failing.


The first step is to verify that your hard drive is in good health and that all bad sectors have been marked as such by the drive.

To do so on Windows:

  1. Click Start > (My) Computer
  2. Locate the hard drive Steam is installed on. By default, this is C:
  3. Right-click this drive and select Properties.
  4. Click the Tools tab.
  5. In the Error-checking category, click Check now...
  6. In the dialog that appears, check "Automatically fix file system errors" and "Scan for and attempt recovery of bad sectors."
  7. Click Start.
    • If you are scanning the C: drive, you will be asked to schedule the disk check the next time you start Windows. Accept, restart your computer, and allow the disk check to start—do not press any keys to skip the disk check.
  8. Allow the disk check to complete. This process may take up to several hours, depending on the size of your hard drive and the number of errors.

To do so on OS X:

1. Open Disk Utility.
2. Select your harddrive.
3. Click First Aid and follow the prompts.

Once your hard drive has been checked, verify the integrity of the game files

Please see Verify Integrity of Game Files for instructions.

If you are still seeing this error, move your Steam installation.

We recommend testing on another hard drive, but you can also try installing Steam in another folder such as C:\Steam\

We also recommend redownloading the game instead of using your existing files—you can back up your steamapps folder in the meantime.

The reasons for doing so are multiple:

  • It ensures a fresh copy of the files are downloaded.
  • It will generally install the files to a new physical location on your hard drive, avoiding the physical location that the issues are occurring at.
  • If there is an issue with your Steam installation, or a bug with Steam, it will reset the state of your Steam installation, possibly preventing the issue from reoccurring.

Please see the article on Moving a Steam Installation and Games.

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