This happens if Run logon scripts synchronously is configured for computers and users in Group Policy.
If you enable this policy, Windows Explorer does not start until the logon scripts have finished running. This setting assures that logon script processing is complete before the user starts working, but it can delay the appearance of the desktop.
If you disable this policy or do not configure it, the logon scripts and Windows Explorer are not synchronized and can run simultaneously.
To resolve the issue for delayed logon process perform the steps below:-
1) Open the gpmc.msc
And make sure “Run logon scripts synchronously” is not configured for any logon scripts.
You can open group policy management console by typing gpmc.msc in “Run”
Then perform the following:
1)Under “User configuration”
->administrative template-> system->scripts-> “Run logon scripts synchronously” -à Make it “Not configured”