Fixing ArcMap crashes

[#1]

Here's a cheat sheet of how to fix crashing ArcMap. An ArcMap "crash" is when ArcMap abruptly closes, or closes with a popup referencing an application error.

Stop going down the list when things are working again. Good luck!

1. If you get crashes on one mxd or dataset the mxd or data may be corrupted. Copy your layers, start a new blank MXD, paste to the new data frame. If it's a complex MXD that would take a lot of time to rebuild from scratch, try to repair the mxd with MXD Doctor. Back up your data and try to rebuild a dataset that is making things crash.
2. Is there an system resources issue? (full C drive, %TEMP% pointing to a non-existent folder, etc)
3. Can another user log into your machine and successfully do the workflow without a crash?
   If so, Reset your ArcGIS application profile (first, try a rename of Normal.mxt, then whole ESRI profile, then the registry)
4. Make sure your display adapter drivers are up to date. This is a likely fix if ArcMap fails on startup when ArcCatalog starts up just fine.  (One time I actually had to downgrade a very new display driver to get things working, but usually the most current is best.)
5. Start ArcMap with the log file option. Maybe the output will give you a clue.
6. Go to Add/Remove Programs - right click ArcGIS Desktop - Repair
7. A full uninstall/reinstall of ArcGIS should be a last resort, unless it's time to update anyway.

References

ArcMap 10.2 crashing when opening .mxd files - Geographic Information Systems Stack Exchange

32797 - ArcMap.exe has encountered an error and needs to close. We apologize for the inconvenience

29936 - ArcMap crashes when trying to start, but ArcCatalog starts correctly

Having trouble starting ArcMap 10? — Esri UK

[AmyKlug]

UPDATE: I was able to, in Catalog, highlight all feature classes and deselect the bad one and copy the good data to another gdb where I can use my python script with iterators.

Any idea how to delete a corrupt feature class that crashes python window, ModelBuilder, ArcMap and Pro when you click on it or call it in code? it's in a feature dataset with our parcel data so it's quite a bit of work to start over.

[curtvprice]

You could try the Repair Geometry tool on your bad feature class. 

[JoshuaDalton]

Also check your source data account if connecting to sde, and if oracle and 10.2 crashes, but 10.3+ works, it may be because you never added select_catalog_role to your sde user accounts.

Additional tricks: export all layers using a newer version using this python and try dragging them into a new mxd file to see which layer is bad.

import arcpy
mxd = arcpy.mapping.MapDocument("CURRENT")
for lyr in arcpy.mapping.ListLayers(mxd):
   lyr.saveACopy("layers\"+lyr.name+".lyr","10.1")

Or, disconnect network cord, and open your mxd, then when all layers have dead connections, fix their sources to corrected sde account and layer.