Windows 10 is very slow to login

You should use xperf to troubleshoot slow logons.

1. install the WPT
2. logon to an admin account
3. open a cmd.exe and run this command:

xperf -on base+latency+dispatcher+NetworkTrace+Registry+FileIO -stackWalk CSwitch+ReadyThread+ThreadCreate+Profile -BufferSize 1024 -start UserTrace -on "Microsoft-Windows-Shell-Core+Microsoft-Windows-Wininit+Microsoft-Windows-Folder Redirection+Microsoft-Windows-User Profiles Service+Microsoft-Windows-GroupPolicy+Microsoft-Windows-Winlogon+Microsoft-Windows-Security-Kerberos+Microsoft-Windows-User Profiles General+e5ba83f6-07d0-46b1-8bc7-7e669a1d31dc+63b530f8-29c9-4880-a5b4-b8179096e7b8+2f07e2ee-15db-40f1-90ef-9d7ba282188a" -BufferSize 1024 -MinBuffers 64 -MaxBuffers 128 -MaxFile 1024

4. Press CTRL+ALT+DEL and then Switch User.
5. Logon with the user account experiencing the slow user logon to reproduce the issue.
6. in the slow account, open a elevated/admin command prompt and run this:

xperf -stop -stop UserTrace -d merged.etl

7. open the merged.etl in WPA.exe, look in the Generic Events for events with matching Start/Stop Opcodes and look which Event has a long duration.

If you need help, compress the merged.etl as 7z/RAR (to reduce the size) and share it (oneDrive, dropbox, google drive).