eM Client being extremely slow, constantly 'doing something' and crashing

We use eM Client on both computers, but we are having problems with it on my partners computer. This morning it has started to run extremely slowly (taking 5-10 minutes to open an email), is constantly ‘thinking’ about something and has crashed on a couple of occasions. It’s even making the computer run very slowly.

We have restarted the computer and the client numerous times, shut down everything in the background, and yet it is still happening.

The client on my own computer is absolutely fine.

Any ideas what this could be?

Hello Leia, can you please make a screenshot of the error you’re seeing and submit it to us here on the forum? What version of eM Client are you currently using on your computer, can you please check the exact release number in Help > About? If the application crashes does it crash intermittently or when trying to perform a specific action, possibly during sync?

Can you copy the error from the crash report log and submit it to us here on the forum? Also what mail service are you using with eM Client?