iTunes can't remember library file location
I am using iTunes on a late-model Dell PC with Windows 7. All software up to date.
With the latest update, iTunes seems to be unable to remember the location of my library file. If I start iTunes normally, it thinks it's the first time I've ever run it and asks me to agree to the EULA, notifies me that it's not the default player for certain files, ask consent to submit music info to Apple, give me a tour of the software, etc.
If I hold SHIFT while starting iTunes, I can choose my library file. After this, iTunes works fine and dandy. However, if I exit iTunes and then reopen it again normally, it has amnesia and we're back to square 1.
My library file is on internal hard drive "D". The actual media files are located on a big external drive "K". My "C" drive is a solid state drive with limited space, so there is no media or music files stored there.
Any ideas on how I can get iTunes to remember where my library file is located? Or must I move my library file to another spot where iTunes thinks it should be?