The log of 3ds Max is located at %LOCALAPPDATA%\Autodesk\3dsMax\XXXX - 64bit\ENU\Network\Max.log where XXXX should be the version of 3ds Max.

You can easily open this file with notepad or any other text editor.

If your 3ds Max crashed during a job and Render Manager reported this error: “An unexpected exception has occurred”, it is good practice to search for this line in the log towards the bottom and then read the lines above that. Most likely you will find the cause of the problem that lead to the crash.

Please note that by default 3ds Max clears its log file very frequently and any additional step taken after the incident that you are looking for might remove the error that you are looking for. You can change the number of log files maintained in the 3ds Max Presences > Files > Log File Maintenance