A blank PrintUI InDesign panel is shown in InDesign

1. On Mac - For InDesign 2017, open the terminal app and enter: defaults write com.adobe.CSXS.7 PlayerDebugMode 1 
2. On Mac - For InDesign 2018 use: defaults write com.adobe.CSXS.8 PlayerDebugMode 1
3. Then Restart InDesign and open the panel.

You can also try clearing your PrintUI Management panel preferences. You can do that two ways:

1. In the upper right corner of the panel is a flyout menu, where you log in, click the Clear Preferences. Close InDesign and then reopen it.
2. You can manually delete the Preferences by going here:
   1. On Mac: ~/Library/Application Support/PrintUI.com
   2. On Windows: C:\Users\<user name>\AppData\Roaming\PrintUI.com
   3. Delete the PrintUI.com folder
   4. Close InDesign and then reopen it.