When saving certain scene files, the Autosave/Autobackup feature in 3Ds Max 2018 takes much longer than doing a "regular" Save to disk, even to fast SSD media.

Possible issues with the "AutoBackupBailout" feature in 3Ds Max, which allows users to cancel an Autosave in progress.

Use Maxscript.
This solution works only on 3Ds Max 2018.

1. Download and unzip AutoSaveSpeedup.zip
2. Copy file AutoSaveSpeedup.ms to C:/Program Files/Autodesk/3Ds Max 2018/Scripts/Startup folder
3. Restart 3Ds Max

Change option in 3dsmax.ini.
This solution works only on 3Ds Max 2018.

1. Navigate to the C:/Users/UserName/AppData/Local/Autodesk/3dsMax/2018 - 64bit/ENU folder. (If the AppData folder isn't visible, change the Windows Explorer → View Folder Options to View Hidden Files and Folders, or View Hidden Items in Windows 10)
2. Open the 3dsmax.ini file in Windows Notepad
3. Under the Performance section, add the following line: AutoBackupBailoutEnabled=0
4. Save the 3dsmax.ini