Introduction
If you will need to use ArcGIS in areas without an Internet connection, you can check out a license by following these steps. This can be used for a limited time and returned once finished.
Procedure
Checking Out a License
Step 1
Once logged in, go to Settings.

Step 2
Click on Licensing and check the check box under Settings for Authorize ArcGIS Pro to work offline.

Step 3
You will be prompted to log in again as part of checking out that license. Click Yes. Follow the login prompts.

Step 4
Once that is complete, you should see that your account is authorized to work offline.

Checking License Back In
Step 1
Once you do not need the license any more, you can check the license back in. While connected to the Internet, open ArcGIS Pro and sign in if needed.

Step 2
Go to Settings.

Step 3
Click on Licensing and uncheck the check box under Settings for Authorize ArcGIS Pro to work offline.

Step 4
You will be prompted to sign in again to check in the license. Click OK and follow the login prompts.

Step 5
Once the license is checked back in, you won't see that check box checked any more.
