4 crashes in 10 min

Hi,

This looks like Java/OS issue.

Did you check your RAM health?

I purchased second hand imac this february - but never had issues with this

Any app you recommend to check this ? 

I got this recently 

Any recommended value ? 

I did not do anything special

Hmm. It looks like your project just needs more RAM than our default limit suggests.

> Any recommended value ? 

Please go to Help > Diagnostic > Change memory settings, set the limit there to 1500, press Save and Restart and check how it will behave afterwards.