I've been using FARR for a while without incident, but recently (and stupidly, as it turns out) upgraded one of my machines from W8 to W8.1. This seems to have broken FARRAltTab, as well as all other programs (FARRGoogleCalendar, FARREnvironmentVariables) that use Vitalyb's C# SDK. On launch, FARR appears briefly in the notification area, then immediately crashes. If FARR is run without the plugin and it's then introduced, it also crashes immediately but sometimes gives the Windows "trying to find a solution" message first. FARR runs fine with the plugins removed.
I've tried a full reinstall of FARR, as well as reinstalling the C++ redistributable package mentioned in the C# SDK thread. Neither has made a difference. According to DcUpdater, everything is up to date. FARRAltTab continues to run just fine on my W7 desktop, and ran without any problems up until the update to W8.1, so I'm pretty sure that's what broke it.