The problem still exists unto MM5 build 2336. After adding files to my MM library from a folder outside MM with format conversion to MP3 the first two tracks have no added timestamp, and so do not appear in the 'Lately added' playlist. :(
PS: The external folder is stored on the NAS and accessed in MM via 'Folder -> Network'.

Could this thread be transferred or linked to MM4 bug reports in any way?
It happened again for 2 tracks while ripping from CD.

Sorry that I can't confirm for MM5.
MM4 is still in use for CD ripping to FLAC because of the Discogs addon.
MM5 is used for format conversion to MP3 where I can use ID3v2.4 tags.
A conversion failure has not occured yet in MM5. :) So ...

This is MM5, are you saying it now works in MM5, but not MM4?

The same issue as in my last post.
So it seems to be a MM4 bug in the replace function for long.

Experienced this again in MM4 while ripping from CD.
- one track (say #5) had an error
- after the rip of the rest the window with the failed track popped up and I selected 'Retry' for this track
- next popup said that the item already exists, 'Replace' was selected
- rip finished successfully, but without 'Added' timestamp for this track.
Maybe this can help.

Sorry, but I really can't remember whether I was questioned to replace existing files or not.
Obviously this happens rather rarely, as after checking my library (about 28.000 tracks, 3.800 of them FLAC) there was only 1 additional track without Added-date in MM5 and 2 (total) in MM4.
The additional track from MM5 is ripped with MM4 and has no Added-date there too.
For the other track in MM4 I'm rather sure to remember that there was a problem with the rip, also the timestamp shows that it was created 1 day later than the rest of the album.

As this neither occurs often nor is a big bug I wouldn't mind if you drop the whole thing.

Are you saying that the first 2 files failed both conversions (WAV > FLAC and FLAC to MP3) ?

Sorry, could not reproduce [b]BUT[/b]
maybe it is something I already realized in MM4:
If a rip/format conversion failed for one track or another and you select the 'Repeat' option for those tracks they don't have an 'Added' timestamp.

A debug log as requested above would be best to help resolve this.

[url=https://ibb.co/ZGfBckT][img]https://i.ibb.co/wBdSpx6/MM5-2259-2020-07-10-16-23-05.jpg[/img][/url]
Screenshot of affected files.
They are not corrupted or changed in audio content.

Screenshots: https://www.mediamonkey.com/support/index.php?/Knowledgebase/Article/View/256/0/adding-images-to-forum-posts

Or open a Support Ticket and attach the files there if that's easier.

[quote=Lowlander post_id=470210 time=1594332151 user_id=262]
Which version of MediaMonkey?
[/quote]
Build 2259 was used with Win 10 (2004, x64).
Don't know how to attach a screenshot here.

[quote=Lowlander post_id=470210 time=1594332151 user_id=262]
In that case the result is expected as both FLAC and MP3 copy belong to the same Album.
[/quote]
Already thought that this behaviour is intended.

Which version of MediaMonkey?

I tried to convert an Album (WAV) not in the Library to an Album (MP3) to be added to the Library and all files show Added as expected. If you can reproduce on build 2259 can you capture this in a debug log (step 4b) and attach the log to a Support Ticket: https://www.mediamonkey.com/forum/viewtopic.php?f=30&t=86643

[quote=PeterXXX post_id=470207 time=1594330793 user_id=87118]If I click one of these albums in one of these playlists the tracks are listed twice showing both formats.[/quote]Do you mean that you're viewing the Album in MediaMonkey after this? In that case the result is expected as both FLAC and MP3 copy belong to the same Album. If this is not it, please detail exactly (a screencast or screenshots may help) what you're doing when you 'click on an Album'.

Format conversion from WAV files (not in library) to FLAC (to library) had no 'Added' timestamp in the first 2 (of 10) tracks. Also after later conversion from FLAC to MP3 of these files, stored in different folders of the library, the same occured.
Furthermore I have different playlists for 'Recently added (FLAC)' resp. '... (MP3)', which often contain the same albums (in different folders). If I click one of these albums in one of these playlists the tracks are listed twice showing both formats.