Some strings do not translate

Symptom: After importing a translation, some strings on your site are translated, some are not.

Possible causes (and solutions):

1. The imported translation is not complete. Consider finishing it and contributing your update by filing an issue against the translation.
2. The actual source strings have been modified after the translation file was created. You might need to update the PO file from a fresh POT file (translation template). The latest core POT files are always available for download, but you might need to generate fresh POT files yourself.
3. There are end-of-line inconsistencies between the actual source strings and the source strings from the PO file. All Drupal files have Unix-style end-of-lines (\n), but these sometimes get messed up on Windows (which normally uses \r\n). WinZip users beware: Make sure the "TAR file smart CR/LF conversion" option is not checked before extracting any Drupal tarball.