Run SFC first

sfc /scannow

Corrupted system DLLs are the most common cause of Explorer crashes. SFC replaces them.

Find the crashing extension

Open ShellExView (NirSoft, free). It lists all shell extensions. Sort by company — disable all non-Microsoft extensions (select all → right-click → Disable). If Explorer stabilises, re-enable in batches to find the culprit. Common offenders: old antivirus context menu extensions, archive tools.

Clear File Explorer history

File Explorer → View → Options → General tab → Clear under Privacy. Corrupted Quick Access history causes crashes on folder open.

Separate Explorer processes

File Explorer → View → Options → View tab → enable "Launch folder windows in a separate process". Isolates crashes to individual windows instead of taking down the whole shell.