How to lock/protect tags of mp3 files from being edited

As the previous posters have mentioned, use id3v2, preferably v2.3.

Sometimes, tracking down problems with tags can be quite painful and in some cases it's easier to remove all the tags and start fresh. That said, one of the useful features of Mp3Tag is it's export function. I've used this several times to find the problem in the 'raw' data.

Essentially, export a well formatted track and one that has a problem, either to csv or txt and compare the two. Using this method shows differences that aren't displayed in the standard interface. You can fix the problem and then re-import.

It seems that this is actually the normal behaviour. USB memory sticks show up in Windows Media player but only for syncing files - there is no play option. The only way I could find of opening the files is to use File -> Open... from the main menu. It is possible to open several files at once by dragging a selection rectangle over them.

I used to use Media Player to play from my external hard drive by setting it as a library location but this isn't allowed with most memory sticks as they Media Player detects that they are removable devices.

If you have a spare external hard drive then you could try using that instead and add it to Windows Media Player's library locations. To do this, right-click Music in the left-hand pane, then choose Manage Music library and click the Add... button.

Unless you are really set on using Windows Media Player, my advice is to download foobar2000 and install it on to the memory stick in portable mode - suitable for use at work as no files need to be installed on the host computer. Using Library -> Configure you can tell it to look at a folder on the drive that contains music, and any new files get indexed automatically.