Last week, US mobile firm Verizon announced a deal with Microsoft to allow subscribers to listen to music on their phones. But it has now emerged that people signing up to the new service are losing the ability to play MP3s on their phones.
The company said the decision was made to keep things simpler for users - one media player rather than two.
If you transfer music from your PC to your phone the software will automatically convert the MP3s to Microsoft's WMA format. Unless you are trying to move music from a Linux or Mac machine, in which case the process may be more complicated.
The VCast Music Service goes live 16 January and will offer half a million songs for $1.99 each. Punters will get a version for their phone and one for their computer.
A Microsoft spokesman said there was nothing in the deal with Verizon or in the company's technology to prevent phones working with other formats.
Verizon is joining the rush of mobile firms trying to extract revenues from music and video while satisfying content companies' desire for solid digital rights management. ®