A nasty Windows 11 bug is causing the C drive plans to become inaccessible in select devices, says Microsoft - XDA

Corroborated by 3 sources from 3 publishers

globaltech3d ago

TL;DR

Reports differ across sources; according to xda-developers.com, summary - The Windows 11 Feb update (KB5077181) locks some Samsung PCs out of C: with a "C:\ is not accessible" error.

Sources