Crashes when using both. I was reading where you could change the "VIEW" to "DEFAULT" and that would fix the problem, but in my case that did not work.
Once the tool is in the part, the part becomes unusable. And the part is also in the assembly, so the assembly is unusable. You cannot open either. If you try, it will crash Solidworks immediately. I also tried deleting the tool from my library, but had no effect. Still crashes.
Can you check it on any other machine? Also once you've placed the form tool into the part, press Alt + Tab key and check if there is any other pop up window that you might have to click.
Does it crashes when using available form tools OR a custom made. Can you run the Rx tool to find issue and send the report to your VAR?
What SOLIDWORKS version and SP you're running?Which Windows?