What I like to do in these situations is
- First and foremost, force save!
in case the following steps crashes my drawing which can happen with these lost entities. You could try a Save As at this point but sometimes those crash when trying to save and you could loose work done since the last save. I prefer the force save myself.
- Zoom into where my main drawing entities are
- Cut my good stuff to the clipboard
- Preform an Erase, Select All (Ctrl+A) (note your attention bar at this step to see what gets deleted)
- Then Paste my main entities back into my drawings using Absolute Zero, making sure my enlargement factors are set to 1, original layers is on.
- If everything looks good, Force Save again.
- Try my zoom extents or GTV with extents and see if things are working as expected.
- If good, close and save file and maybe run a File, Repair for a final bit of scrubbing.