There are a variety of reasons that can cause this type of problem in AutoCAD, like saving to dropbox or a remote server, but one interesting one is a setting in AutoCAD.
If you have the Express Tools installed you can redirect where the backup (.bak) files are stored. In this case, the server had been decommissioned!
Check the MOVEBAK variable and ensure it's set to your local hard drive for quicker saves.
Enter MOVEBAK at the command line and hit enter:
Initializing...MOVEBAK command loaded.New value for MOVEBAK, or . for none <>:
That is the default a period (.) for none.
If it is set to something different, then make note of it and enter a . for none and see if your saves are faster!
another troubleshooting tip is to turn off making the backup file to see if it makes a difference.
From the Help file:
MOVEBAK (Express Tool)
Changes the destination folder for drawing backup (BAK) files.
Once you specify a folder, the drawing's BAK file is placed in that folder after every save operation.
Enter new value for MOVEBAK, or . for none <current setting>:
Enter a . (period) for none or type the folder name
If you enter ".", the MOVEBAK folder name is cleared and new BAK files will be created in the original folder.
Note: Creating BAK files is optional, but recommended. The system variable ISAVEBAK controls whether BAK files are created each time the drawing is saved. You can also enable this function from the Open and Save tab of the Options dialog box.