HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\ DWORD: DebugLog = 1 DWORD: DebugLevel = 3 Logs appear in %USERPROFILE%\Documents\RDP Debug\ — includes TCP/UDP negotiation, certificate warnings, and bandwidth decisions. Saved .rdp files store passwords with Windows Data Protection API (DPAPI) — tied to your Windows user and machine. Interesting failure: If you migrate a saved .rdp file to another PC or even a different user profile on the same PC, the password silently fails. mstsc will prompt again but never tells you the stored password is invalid — it just re-prompts.

Ensure UDP 3389 is allowed bidirectionally. Force UDP test:

`usbdevicestoredirect:s:* 4. Logging What MSTSC Doesn't Tell You mstsc has verbose logging disabled by default. Enable it to see exactly why a connection fails or is slow: