Poweramp: Unknown Album, Unknown Artist.
This was an issue that was driving me nuts but I was eventually able to solve it by trial and error.
What I found is a problem when special character is used in the Contributing Artist field of the Meta Data. In my case (I am using mp3 files) and the specific character was and ampersand ?&?. . Not sure what other special characters this may apply to but when I cleared the Contributing Artist field the issue went away.
Interesting that poweramp does not display the Contributing Artist field.
In any event the way I went about resolving the problem was to first delete the files from my phone using poweramp. Then to change the meta data for the files on my main computer (My files are stored on a windows 7 computer)using the following method.
This post came from Bakoro on the windows 7 forum:
?1.Highlight all the files that you wish to clear any sort of meta data from.
2.Right click and go to properties.
3.Click on the Details tab.
4.At the bottom of the Details tab, there is something that says "Remove Properties and Personal Information. Click on it. Don't worry it won't ruin anything.
5. A new panel will pop up, click on the second bubble option and BAM, you can select all the info that you want to clear for all those 93GB of music that were ruining your MP3 player artist lists or album lists or what ever.?
I used this method to clear the contributing artist field, then reloaded my files onto the phone. (I just drag and drop the files from my computer to my phone using a usb connection).
When I disconnected the phone and brought up poweramp there was no longer an issue.
Hope this helps