I installed P2A_2401_x64 to a clean directory not on the C drive. I then ran Nav Data Pro to install airac 1708 to match what I have installed in XP11.10r3 (official release).

Running Windows 10 Home.  When I run P2A, it starts up OK and many functions would appear to work (e.g., runway info, TERPs, basic airport info, but it seems to find no radio frequencies for any airport.  I've tried KSBP, KSMX, KSBA, KLAX, and KSFO.  I'm using the info pop-up to check for the frequencies.  The frequencies list in that popup always is empty.  Likewise, clicking the Freq button in the left panel brings up no frequencies for the selected airport and  doesn't even pop up any window.  No errors are reported.

I have tried the following:
1.)  Starting and stopping the database server with the commands:
       >SQLLocalDB stop "MSSQLLocalDB"
       >SQLLocalDB start "MSSQLLocalDB"
2.)  Deleting the .ldf files and restarting the database server.
3.)  Running P2A 2.2.2.1 with airac 1708 -- found that it still sees controller frequencies correctly for selected airports OK.
4.)  Restoring airac 1706 from the backup created by Nav Data Pro.  Got Database Error: Unable to initialize Database.  The underlying provider failed on Open.  An attempt to attach an auto-named database for file D:\Pilot2ATC_2018_x64\Data\P2ABaseData.mdf failed.  A database with the same name exists.

I have MSSQL 2012 and 2014 servers installed on my system.

Next I will try a clean re-install of P2A_2401_x64 and see how that works with the airac 1706 that it comes with it.  Need to reboot my machine for that, most likely.

 

 

 

I rebooted my system and installed a clean copy of P2A_2401_x64 including the airac 1706 that it comes with.

This combination works OK.  I see the frequencies at the airports using the Info popup in the right panel. Does this imply that the Nav Data Pro airac install was not good?

However, clicking the Freq button produces no popup, which is troublesome but not a gamestopper.
 

The ATCSettings has Controller Radius as follows:
Tower: 10
Departure: 15
Approach: 15
ATC Center: 40
Controller Name Radius: 25
 

I ran Nav Data Pro to update my Pilot2ATC airac from 1706 to 1708.  Now, the problem has returned:  no controller frequencies show up in the Info popup in the right panel.

This seems to indicate a problem with the interpretation by P2A_2401_x64 of the airac 1708 database installed by Nav Data Pro (version 1.0.6.0) into its Data folder.  I say "interpretation" because my P2A 2.2.2.1 interprets the exact same airac 1708 data just fine, which indicates the data itself is OK or at least present.

Any suggestions?

The NavDataPro 1706 that ships with Pilot2ATC contains controller information.  NavDataPro 1713 and higher will contain controller information, but version prior to that from NavDataPro do not.  So you should stick with the 1706 that's bundled with P2A or update to 1713 or later.

Dave