System Information
Operating system: Windows 10
Graphics card: Intel® HD Graphics 620 (Kaby Lake GT2)
Processor: Intel® Core™ i3-7020U CPU @ 2.30GHz × 4 (64-bit)
Memory: 8 GB

Blender Version
Blender 2.80 RC2

Short description of error
Was texture painting and didn't have base image saved to a file yet. Clicked "Save all images" in the "Context" menu and Blender crashed.

Exact steps for others to reproduce the error

1. Use texture paint tab
2. Under material, add a base color texture
3. Click "save all images" without saving the texture to anywhere