Export to MP3 stopped working

Any ideas why I can’t export to MP3 any more? Audacity file seems to export and creates an MP3 file of approx correct size, but there is nothing there on playback. I’m doing this on my laptop on which I recently reinstalled Audacity. I’ve tried reinstalling it again, and also re-installing LAME, but it still does the same. When I copied the Audacity files over to my desktop, also running 2.1.2, it exports and plays correctly. Am I missing something obvious with my laptop setup? When I attempted to upload the MP3 to an online database, I got an error message on the MP3 upload. I’ve been exporting MP3s regularly over the past few weeks from it with no problems, but now, nothing.

In what application are you playing the files on the problem computer? Does the time counter go round? If so, is that application playing to the default Windows playback device, and is that device the one you are connecting your speakers or headphones to?

2.1.2 defaults to exporting as Variable bit rate. This is unlikely to be suitable for streaming online, so consider exporting as Constant bit rate instead.