Google Music's new free online music locker has run into an inevitable, often popular fact of the music business: some songs have both clean and explicit versions.
Online  reports  have circulated in recent days about explicit versions of songs being replaced in Google Music users' cloud locker with clean versions, annoying customers who want to stream the explicit versions they had originally purchased. Google added the scan-and-match  feature to its online music locker on Dec. 18.
Google Music actually offers an easy way to correct any problems in the matching process. Right-clicking a song or selecting the drop-down menu available next to every song title (look for the small triangle) leads to a menu option called "Fix Incorrect Match." That option will allow the user to upload a particular version of a song and override Google's matched version. The "Fix Incorrect Match" option is available only for matched songs, not uploaded songs.
The mismatching problem arises from the way Google Music matches a user's music collection against its licensed catalog. According to a source at Google, the company uses its own technology to listen to a short snippet of a song rather than the entire song. Google does use Gracenote for some services, such as providing album artwork, but does not use Gracenote for the scan-and-match service, the source said.
Other online music lockers have had the same problem. Amazon Cloud Player also has a "fix incorrect match" option to manually select tracks to re-upload to override the match that would be selected by Amazon. iTunes Match does not offer this option and users have been complaining of problems  since the service launched in November 2011.