On Windows Vista and later, client performance can be greatly improved by changing the compatibility settings on Razor or UOSteam. To do this, right-click your Razor or UOSteam shortcut, open Properties → Compatibility. Use the settings specific to your Windows version below.

In addition to the settings below, “Run this program as an administrator” has been known to fix issues. This option is generally not required.

Windows Vista

  • Check “Disable desktop composition”.

Windows 7

  • Check “Disable desktop composition”.
  • Check “Disable visual themes”.

Windows 8, 8.1 and 10

  • Check “Run this program in compatibility mode for” and set it to “Windows XP (Service Pack 3)”.

Razor – Cliloc error

If Razor is unable to find your UO directory, you will be notified with a “No CliLoc” error message.

This can be fixed by adding the older UO registry keys pointing to your UO directory. The required registry keys can be generated using the following form:

Ultima Online directory:

After submitting, you will receive the registry keys in a file named uo.reg. Save this file, and either right-click it and select Merge, or if that option is not available, select Open with → Registry Editor.

Razor – Missing .NET Framework

If the .NET Framework 1.1 is missing from your computer, Razor may give the following error message on startup:

System.ArgumentException: The output char buffer is too small to contain the decoded characters, encoding 'Unicode (UTF-8)' fallback 'System.Text.DecoderReplacementFallback'.

The fix for this is to install the missing framework, available for download here: