PSA: Microsoft released a fucked Defender ASR Definition update today.

It causes Windows to randomly delete .lnk files (shortcuts) from all around the system, including the taskbar and start menu.

The workaround is to go to your configuration management for ASR (I'm assuming Intune here, change for GPO, SCCM or similar) and setting the Defender ASR rule "Win32 imports from Office macro code" to Audit Only.

Clients will then have to sync this policy down until Microsoft gets their shit together. Unfortunately, recovering already deleted shortcuts doesn't have an easy fix.