Students on approved leaves will continue to remain active until a year after their last registered semester. After that, your account will become deactivated and you will lose access to your account (email, Illinoisnet, library, etc.). Students on an approved leave of absence from their college or academic department can be reactivated at the request of their department; please see Identity and Access Management, Affiliate NetID Manager FAQ.

For those who left due to Military Service:

Prior to your return:

Please refer to the following page from the ISSS for more information on returning from a leave of absence: https://isss.illinois.edu/students/returning.html
If you have limited services, please follow all instructions in the link above.

From the Admissions Blog: 

Notify the ISSS at least a couple of months in advance of your return so they can send you the I-20 Form with ample time for you to come back. You must also notify your specific college that you will be coming back and intending to resume your studies. After that, the school will re-activate your student Enterprise account, where you will be able to find your time ticket to register for classes. Another reason to make sure you let the University know early on is that registration for classes often happens at least two or three months ahead of the next semester, so it's necessary to inform the ISSS as soon as possible to make sure you can register on time. Once you receive your new I-20, you are back to where you were before you left!

Upon return:

To reset your password, please visit the NetID Center.