I have many hours into a residential remodel and detached dwelling unit, and just starred getting this error message:

Results of Validity Check.
*** Problems were found that could not be fixed! *** The entity at address 18cb1a0 has an invalid id (0) destroyed (0)

Is there a way for me to find this error and manually fix it? Things seem to be loading into Layout okay, so it looks like the file is actually saving, but this is disturbing.....