Whoops, I didn't notice that you mentioned WASAPI in the original post.

(2) As stated in my original post, I use WASAPI. Can confirm that it is indeed when you rate the current/playing track. Editing other tracks than the currently playing does not give an issue for me. Also confirm what has been said above, no issue when switching to DirectSound.

As I see in the Mantis ticket, I indeed have Smooth stop, smooth pause and smooth seek switched off !

(1) thanks, overlooked the mantis ticket made earlier about this issue.

Can confirm the stutter with WASAPI, even when editing a single track (i use to set just ratings while playing a lot, stutters most of the time for 1, maybe 2 seconds).

Occurs only if i rate the current playing track, seems to make no difference if tag edited in main window or in the player controls in the footer. if i edit another track in the main window, no stuttering.

Changed to DirectSound, Quick Check over 3 tracks, seems to be fine now.

Version is 2299.

2) Tracked as: https://www.ventismedia.com/mantis/view.php?id=17505

2) I can reproduce, but only when the output driver is set to WASAPI. Can you confirm that you're using WASAPI (under Tools > Options > Audio Output (plug-ins); and if so, can you check if it no longer occurs after changing to either DirectSound or waveOut?

Edit: I can still reproduce the issue by just editing the currently-playing track. i.e., playback stutters even when I edit the rating from the player (you can enable rating inside the player with Tools>Option>Player>Metadata)
Can you please confirm if you can reproduce by just editing the currently-playing track?

1) https://www.ventismedia.com/mantis/view.php?id=17503

I run 2404 RC5 regular (no debug version)

Sofar, I observed 2 bugs, or perhaps (1) is by design:

1) My album tracks are collapsed in the View menu. When I play a certain album, I tend to muanually uncollaps the album to show all tracks. The moment, during playing, the 'last played' is updated, the album collapses again. This was not the case in MM4, there the album which I manually uncollapsed stayed that way until I collapsed it manually again (or automatically when I changed the view altogether, for instance browsing a new playlist).

2) When, during playing, I manually update the rating of the album that is playing, my music stutters for a fraction of a second and/or I hear a annoying click, all depending on the size of the album (eg. the number of tracks to update). Other types of updates have, more or less, the same behaviour. MM4 uses the same database (140809 tracks placed on conventional harddisks in a Microsoft Storage Space on the local computer where MM4/MM5 is doing the playback) and has no such problems. I use WASAPI in exclusive mode (24/96), no changes in the advanced settings. It is not a big issue as I hardly do manual updates during playback.

Remaining visual bugs for which I was perparing a report, were fixed in RC3 and RC4.