Sadly the only quick fix is uninstalling .NET 4.5 or moving to another server where .NET 4.5 hasn't been installed. 4.5 is an "in place upgrade" as described on http://www.hanselman.com/blog/NETVersioningAndMultiTargetingNET45IsAnInplaceUpgradeToNET40.aspx
As mentioned upgrading the a recent C1 version will fix this issue and if you go with the upgrade service this can be a fairly trivial task.
I'm sorry you are experiencing this. This issue was kind of "stuffed down our throats" at the latest possible hour - we did not experience issues while testing with the .NET 4.5 betas, but the final release did us in :/ But if you go to 3.2 latest patch or 4.x etc. you're all good.
As mentioned upgrading the a recent C1 version will fix this issue and if you go with the upgrade service this can be a fairly trivial task.
I'm sorry you are experiencing this. This issue was kind of "stuffed down our throats" at the latest possible hour - we did not experience issues while testing with the .NET 4.5 betas, but the final release did us in :/ But if you go to 3.2 latest patch or 4.x etc. you're all good.