Unable to use Acrobat Pro, spinning blue circle and greyed out window

[Robert309223697ft2]

I've just installed Adobe Acrobat Pro and when I open the application, it starts okay and then after 20-30 seconds a grey window appears with a spinning blue circle which I assume is a loading bar however it's blocking me from using the application and isn't going away. I've left it for 30 minutes and there is no change. I have the creative cloud for the desktop and it shows that the application is up-to-date I'm all logged in but nothing is happening. Any support or help would be appreciated.

[mariahweyne]

Try changing the Security settings in EDIT-PREFERENCES.  

[Adrian311777783fzg]

Had the same problem and this worked for me. Thank you.

[steve24227631x6da]

I also had this problem and it worked for me.  Thanks.