If your AutoCAD is affected by errors or bugs then you can manually reset AutoCAD to the default setting. But before trying manual reset I would suggest you try the simpler methods as mentioned in the related article below.
In most of the cases these tips can solve the issues but if AutoCAD still ceases to work properly then you can try doing a manual reset which will revert it back to the factory settings.
This method requires you to have administrator privileges as we will make changes in windows registry. Make sure you have closed all instances of Autodesk software before making these changes.
Manual AutoCAD Reset
Press window +R key then type REGEDIT in RUN window and press enter to open the registry editor window. Expand HKEY_CURRENT_USER from the file tree on left then expand Software then Autodesk then AutoCAD then R20.0 or R21.0 whichever is there on the list.
Now select folder ACAD-E001:409 right-click on it and select Export from the contextual menu. Specify a location for saving the registry value and save it. Now right click again on ACAD-0001:409 folder and select delete from the contextual menu and close registry editor window.
Make all hidden folders visible using windows explorer, in windows 10 you can make it visible by checking the Hidden items box from View tab of File Explorer as shown in the image below.
Go to C:\Users\<user name>\AppData\Roaming\Autodesk and rename AutoCAD 20XX folder to AutoCAD 20XX.old.
Go to C:\Users\<user name>\AppData\Local\Autodesk folder and here again rename AutoCAD 20XX folder to AutoCAD 20XX.old.
In the file path mentioned above <user name> will be the username assigned to your PC for example in my case username is Jaiprakash on my PC. Also, the 20XX is the version of AutoCAD software in my case it was 2017.
When all of these changes are done launch AutoCAD software and it will open in out of the box condition and without any errors (at least in most of the cases!).
Reverting to old AutoCAD
If somehow this does not work for your version of AutoCAD then you can revert AutoCAD installation to the previous condition. Double click on the registry file saved in the example above and rename AutoCAD 20XX.old folders to AutoCAD 20XX and then launch AutoCAD again.
Do you have questions related to this tip? Let us know in the comments below.