Library is empty

Hallo all!
I've enable the library (in the option->library menu) but dont work. My mp3 archive is stored in an external NAS.


When open mp3tag, the library is ever empty and reload all the archive (32Gb of music....)
Plz help me!
Thx in advance

How do you know that the library is empty? An empty file list does not mean that the library is empty.
The library eases the handling of large collections (usually more than a TByte).
Access to your files should be quicker when the library is switched on. Yet, as you have stored your collection on a NAS, the network access is probably the bottleneck so that you do not see much of the advantages of the library.
If most of what I wrote does not deal with your problem: could you please explain it again in more details?

How do you know that the mp3tag.db3 is empty?
Are you sure that Mp3tag.exe has write access to this file on your Synology NAS?

BTW: You should save this library on the fastest possible (internal) drive you have. An external NAS is not the best target for a fast access.

And just for the records:
You may already know that Mp3tag doesn't need this library at all. It doesn't work like MediaMonkey who saves all the metdata to such a library. Mp3tag is using his library to speedup the re-reading of huge amounts of files.

Actually there is benefit even when reading files located on network share (NAS).
So far I have tested it on my medium size collection (56K files, ~0.5TB) and re-reading with library is almost twice as fast, as without it.

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OK, point taken.
The fastest is still: library on SSD, collection on separate drive with at least direct SATA interface. Network access is definitely slower esp. if you think about it that every modification leads to reading and writing over the network.

Okay, thank you all. Some considerations: The music Archive on the NAS is great 190Gb and not 32 as I said, sorry. It is essential for me to stay there for convenience and to use the Sonos system.
I searched the library file and it actually was not written on the root folder of the NAS but on my C drive and it is 149Mb (see attached screenshot). Until a few years ago the reading of the archive via network was very fast. A few minutes (2-3). For some time it has become very slow. Since I turn MP3Tag to when I can use it spend at least 8-10 minutes. This is unexplainable to me. My account is admin both locally and on the NAS, and the network is wired 1GB. I thought that by enabling the library, the waiting times would be canceled instead it does exactly as before. At this point I do not understand the meaning of the process. If every time the program rereads the entire archive the library what is the use? Why don't you do this in the background?
Thanks to all and excuse the translation of Google from Italian.

If you want to have the library on the NAS, you have to install MP3tag on the NAS as a portable installation.
Let's go back to the real purpose of a tagging program: it helps you to get files from the status of "no tags" or "badly tagged" to perfect. I would assume that this usually happens at the time when you first get the files. After the tagging you hand them over to your collection and the program that manages that collection.
MP3tag is no collection management program but a tagging program.

So it is up to you to organize your workflow to get the most out of MP3tag and your requirements to store data on the NAS - perhaps you tag the files locally first and then transfer them to the NAS.
You might have seen the contributions by @LyricsLover and @Etz that clearly point out the benefits and drawbacks of a setup with a NAS and the role of the MP3tag library. If you are not satisfied with the library: don't use it, it can be switched off.

@Kermit70 you have probably misunderstood this feature. Mp3tag library is not an actual music library, it is tag database to speed up file access on huge libraries and overcome memory issues when loading them into mp3tag at once.

About slow file access on your NAS, depending on filesystem, it may happen over time. For example btrfs and ntfs have defrag feature to fix file fragmentation (yes, fragmentation happens on network storage as well). Also how full are your drives? Most filesystems don't like if there is very little free space left (rule of thumb is no less than 10-15%).

Without exact knowledge about your HW setup, it is hard to tell, what can be the culprit and how to improve things.

Also, keep in mind that mp3 files themselves are quite small and instead of contigous sequential read/write, they need mostly lots of random read/write operations, which are way slower and more taxing on your NAS CPU. Also random disk access is slower than sequential one.
Hence the overall lower performance on reading/writing comparing to big mkv or iso file.

@ohrenkino I don't think that storing database on NAS would be very wise idea in this case, as you would loose all the performance benefits. When you store library on NAS as well, you would need to read all tag related data from NAS again, which pretty much defeats the purpose. Better to keep it on local fast SSD.


I have the very same problem : no library at all with files on a NAS

How do I know the library is empty ?

  1. The loading time is exactly the same with or without library enabled
  2. No big file in C:\Program Files (x86)\Mp3tag or subdirs. The help says "metadata is first read from the files and then stored in a database that resides in Mp3tag's configuration folder"

My NAS is of course accessible, because MP3tag has otherwise no problem to handle files on it.

I'm well aware thaat MP3tags is not an actual music library. I just want MP3tag to cache metadata in a database so the loading time is better. Thanks for your help !

Capture :

If your music files reside on a NAS, then the network speed is the bottleneck.
You have 1 Gbps network speed vs. 6Gbps SATA bus speed.
So the library is idle most of the time until finally the requested information from then NAS arrives that a file is still there and its state of modification.
So in respect to performance, a NAS is not the best choice.

If you have a huge collection, you should still use the MP3tag library function as otherwise you may run out of memory very soon.

So; "library" caching option is useful with a fast SSD, and useless with slow connection ? This is paradoxal

I don't complain the scan is slow; I complain there is absolutely no time difference with "Library" enabled, and all files are being scanned just like there is no metadata cache

BTW where is the "Mp3tag's configuration folder" , so I can check if the database exists or not ? There is no database file in Mp3tag's folder or subdirs

Does someone achieve to get "Library" to work with NAS ?

You don't seem to read all that is in the posts. The main purpose is to be able to read the files from large collections. Without the library, you can read some 50,000 files before you run into memory trouble.

That you also gain some speed depending on your system setup is a nice by-product.

See this topic on where to look for MP3tag files:

Yes. And the configuration folder is not C:\Program Files (x86)\Mp3tag but in a standard windows-installation %appdata%\Mp3Tag and you find the library in the subfolder \data\library.

As Ohrenkino already wrote it is not a good idea to use a NAS if you want to speed up the loading.
Anyway there is another possible limiting factor if you use the antivirus-software from Microsoft (Defender) as I wrote here:

You have to define an exception for mp3tag.exe in the antivirus-settings of windows.

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This is it !! I disabled temporarily Windows antivirus => super fast loading ! A strange thing is when antivirus is off, the NAS is not even accessed (I know it because the disks stays in sleep mode). If I reenable antivirus, the disks are accessed !!

Thanks for all, and for your speedy answers.

The timestamps of the files on your NAS have to be read at least in order to decide whether the content of the library is up to date or if the library-content has to be actualized.
I don't know whether a cache is working there to explain your observation.
Perhaps you restart windows and then test again.