LR crashes after imports - even after restoring catalogs from backup

I have managed 15+ years of photos on lightroom and use it mostly for management, not a lot of editing, thus I am on 6.14 as I don't need the latest & greatest. 

After a restoring catalog from backup I can open LR and move around, edit photos, etc. After I import it will just die, with no error, nothing.

I'm on 6.14, Windows 10.

What I've done:

• Restored from backed-up catalog so I could run LR again
• Optimized catalog
• Uninstalled/reinstalled LR (removed preferences to clean that up)
• Checked/applied LR updates
• Turned off the GPU setting in preferences/performance
• Imported photos directly from the PC (not a card)
• Used different sets of photos to import to ensure it's not some specific image (but still, should give me an error if that's the case)
• Created new catalogs & imported to ensure it's not a corrupt catalog
• On import, tried copying images rather than moving them

I feel like I've pinpointed that it's the import as I can do everything else until import on multiple catalogs. I've got multiple Temporary Import Data.db & Temporary Import Data.db-journal files in the Lightroom directory which also point to import as the culprit.

Appreciate any diretion you can provide!