One of our clients was having the same problem. Only one user was affected. Did procmon and found the same result. It was checking every file in the Attach folder on startup, and every time they performed an action resulting in it becoming unusable.

Attempted the Quickbooks Tool Hub, Quickbooks Install Diagnostics Tool, Quickbooks Repair, Clean Reinstall (removing all quickbooks data from registry, programdata, localappdata, roaming), and all sorts of other finagling. Nothing worked for us so far.