This issue is starting to get irritating. When I run multiple idb sessions (Version 12.0) on the same system, I periodically get error messages when I try to open source files:
"File not found: /home/emr/.idb_12.0_linux_intel64_app/workspace/External Files/%home%emr%development%enc_png.c"
This problem will persist until I recursively remove the entire .idb_12.0_linux_intel64_app configuration folder and start the debugger up again, naturally losing my window layout preferences. The problem seems to be related to having multiple debugger windows open at the same time.