"Synctoy is unable to determine if other instances of SyncToy are running, possibly because perfmon counters are turned off for some components. Is this the only instance of SyncToy currently running?"

 

Stuffa,

Enabling that perf counter for the PerfProc.Dll addresses this issue and
enables SyncToy to run.

We will take a look at alternative means of determining whether SyncToy is
already running for possible inclusion in a future release.

For those interested, the registry entry for PerfProc is:

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Services\PerfProc\Performance

As you might expect, the Disable Performance Counteres REG_DWORD = 0 for not
disabled and = 1 for disabled.

I hope this helps.

george

Source: SyncToy not running – throws System.InvalidOperationException-Usenet Gateway

Reading a blog about a similar problem I decided to finally see if I could finally find an answer to an annoyance I have with Synctoy. Other than this annoyance I really like Synctoy. I changed the Disable Performance Counters to 0 in the CurrentControlSet rather than the ControlSet001 and it  fixed my problem. From what others have written about this problem, this is the typical solution recommended but it did not work for some people.