Visual Studio 2015 Update 1 repair error

I'm attempting to repair VS2015 with Update 1 installation due to the following error when loading projects:

• Project 'projectName' could not be opened because the Visual C# 2015 compiler could not be created. Please re-install Visual Studio.
• .cs files are loaded as white plain text
• "An error occurred loading this property page" error occurs when opening some of the C# Text Editor options.

However the repair fails with the following error:

[15D4:410C][2015-12-07T11:08:31]i301: Applying execute package: vs_minshellres, action: Repair, path: C:\ProgramData\Package Cache{7FF53256-7BAF-3EFA-91B4-DB65F37EB5E9}v14.0.23107\packages\vs_minshellres\vs_minshellres.msi, arguments: ' MSIFASTINSTALL="7" VSEXTUI="1"' [43D0:2388][2015-12-07T11:08:40]i000: MUX: ExecuteError: Package (vs_minshellres) failed: Error Message Id: 1316 ErrorMessage: The specified account already exists.

[15D4:410C][2015-12-07T11:08:41]e000: Error 0x80070643: Failed to run maintanance mode for MSI package. [15D4:410C][2015-12-07T11:08:41]e000: Error 0x80070643: Failed to execute MSI package. [43D0:2388][2015-12-07T11:08:41]e000: Error 0x80070643: Failed to configure per-machine MSI package.

Thanks to @Daniel Hakimi and @scofield_foxriver for your input.

After uninstalling VS2015 Enterprise and its related components, restarting and Re-installing it's working now.