Can't comment so posting...
If %USERPROFILE%\AppData\Local\Temp
doesn't contain an SSMS folder, another option is to check
%USERPROFILE%\AppData\Roaming\Microsoft\SQL Server Management Studio\[your version number]_IsoShell\AutoRecoverDat
If you find a DAT file with number as the name, this file contains paths to other temporary sql files as shown below
System I was on does not use SSMS 2017 so never would have thought to check there...
Best of luck to everyone landing here :)