Sometimes can be situations when you can't find utility for recover AutoCAD online by normal or usual methods. You may refer to following instruments like:

If a file cannot be opened, take the following steps:

1 RECOVER command
- Recovers a selected drawing file
- If successful, open and run AUDIT command
- Evaluates drawing integrity and possibly more error correction
- Set system variable AUDITCTL=1 to create a report of audit results

2 RECOVERALL command
- Recovers a selected drawing file
- Attached and nested xrefs are also opened, repaired, resaved, and closed

3 INSERT and EXPLODE

4 Start a new DWG with no template
- Run INSERT and selected the corrupted drawing
- Check the “Explode” option

https://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/AutoCAD-File-Corruption.html
http://www.cad-addict.com/2009/07/autocad-use-autosave-files-to-recover.html
https://dwg.recoverytoolbox.com/online/