Running migration jobs with SPMT requires TEMP storage. Often 50+ GB and more than available C:\ drive. We see Windows O/S drive fill 100% with no free storage.
By default SPMT writes temp storage to [C:\Users\%USERNAME%\AppData\Roaming\Microsoft\] in the User Profile for current user running SPMT “microsoft.sharepoint.migrationtool.advancedapp.exe” Note how SPMT installs to the User Profile folder at [C:\Users\%USERNAME%\AppData\Local\Apps\SharePointMigrationTool\SPMT]
Before running SPMT migration, run CMD prompt and MKLINK /D to point a Symbolic Link folder and move TEMP drive. SPMT application will see the same original folder. However, files and folders added written are directed to different destination. Avoids full C:\ drive and halted migration. Cheers.
REM — REPLACE DRIVE LETTER X: AS NEEDED —
mklink /D MigrationToolStorage X:\MigrationToolStorage