Haven't seen that, is your user a local administrator? If you're not sure, check the Windows documentation on your system regarding "account types," then review your User Accounts control panel.
All: please read through the Release Notes (also posted here as the first post), paying particular notice to
Known Issues. It might save you some time and frustration.
BTW, I've confirmed the "error" in the count during the momentary "writing" footer ... I can't find it in the code, but I believe it's indicating WHICH TRACK is being submitted to MM to re-tagging, not progress on how many overall are being written. In the following screenshot, it's queuing track #16 of 20 for writing ... NOT 16th track with lyrics found (because there weren't that many found, only 13 had results). Note that the 16th track is highlighted in bright green.

So I don't think this is a bug, but a misinterpretation of the message.
