I have 3 devices. A Windows desktop computer and an Android phone. They work fine. I have added a Windows laptop. I exported all the notes from the desktop and imported to the laptop. If I try to sync from the laptop, it will work for hours, but it does not sync any new notes I have created. In the Sync status Window on the desktop I have Total: 13073/13073. On the laptop Total: 12529/12529. Any ideas what the problem is?
It's difficult to say what exactly has been going on without detailed logs, however, for the record, when using synchronisation, you're not supposed to import the same notes manually, but you should rather rely on the sync mechanism to "import" them to the new device. This is because when importing notes manually, they get new IDs and are treated as different than the originals by Joplin.