Do you run any clean up of accounts on the machine? Or are all 1000 all saved with local folders? How full are the drives?

Gabe Shackney
Princeton Public Schools

If your JSS is not set to process login items in the background then login policies will slow the login process until they have completed.
Enabling it though can mean reworking some of those policies to make sure they behave correctly.
If it's already enabled then login policies will generally not impact login times.
There is also an AD timeout you can adjust that can help (I think it's set to 2 minutes by default) In general if it hasn't found whatever it's looking for within a few seconds it probably never will!

defaults write /Library/Preferences/com.apple.loginwindow DSBindTimeout -int 10

It might be the problem Sharepoint files discussed at https://www.jamf.com/jamf-nation/discussions/19988/stuck-on-startup
Different OS version, but maybe.
In that case folks were cleaning up accounts, but leaving behind some Sharepoint files that were all parsed during startup. The heavier use, the more to parse.

Thank you for the replies and helpful suggestions so far.

I do clean out accounts after 14 days of inactivity but my process only removes the user directory. Therefore, I am wondering if this is caused by something left over outside of the user's directory. The Sharepoint files don't seem to be a problem on my computers since only the truly "local" account has a file there. I'll have to look for other system files like this that record the users.

One tip you can do is to add some debug "echo" or touch commands to you scripts. After each action have it echo the timestamp to a log file or touch a blank file to a hidden location and view the timestamp. It sounds like it is happening before your scripts and policies but if I suspect my policies or scripts may be causing an issue, I make to leave commented out "echo" lines in them so I can turn them on in such situations.