This is the error message I receive when Xcode crashes as I try to add images to a tile set. The images came from Itch Co and are part of the Kenney.nl asset bundle mentioned in the duck tile map game on raywenderlich.com.
The crash occurred immediately as I released the mouse from a drag and drop to add the image, but only on addition of the 6th image. I reopened and tried to only add the 6th image in the list and still crashed.
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
*** error for object 0x7fee5627ac00: incorrect checksum for freed object - object was probably modified after being freed.