Hi @Anonymous,
Welcome to the Fusion 360 Community!
Just to check - does this happen every time that you select the "Mirror" command (from the sketch or the Create menu?) as well as the Grid Options from the navigation toolbar along the bottom of the screen - correct? I just want to try to narrow down why this is happening and try to capture reproducible steps for development.
Regarding the save issue - no recovery file is saved upon crashing? For instance, if you went to the File menu and then select Recover Files - a backup file of the latest worked model is not there?
Can you do me a favor and go to your help menu and select Graphics Diagnostics and post a screenshot of the screen that pops up. While in this menu, can you try selecting "Limit all effects to increase performance" and then try the mirror command again. Does it still crash? Next to Driver API what does it say it is using - DirectX 9 or 11? Can you then go into your Preferences and on the first screen that pops up, there should be a Graphics Driver selection. Can you try selecting the option (DirectX 9 or 11) that is NOT the one that was highlighted in the graphics diagnostic box. Once you do this you need to restart Fusion for the effect to take place. Once restarted, try the mirror command again. Do you still crash?
Final thought - is this just one file this happens to, or is it computer wide? If it is one file, can you please send me a public link to your design so I can try to test this on my machine.
Thanks,
James Youmatz
Product Insights Specialist for Fusion 360, Simulation, Generative Design