There are the following versions of the message:
If you notice a real performance problem apart from that message, first of all, please try following this guide https://www.jetbrains.com/help/resharper/Speeding_Up_ReSharper.html.
If those steps did not help and you still experience the performance problem, please follow https://resharper-support.jetbrains.com/hc/en-us/articles/207243205 article to send us a perf snapshot.
At the same time, we constantly work on ReSharper performance improvement, but some problems can only be solved by taking ReSharper out of the process. This is a massive architectural challenge and will take some time. The progress can be tracked here: