Why does Serato read tags every time it opens?

What Rescan ID3 Tags actually does

Serato keeps its own copy of each track’s details (artist, title, BPM, key and so on) in its library database, and reads the full data, including cue points, loops and beatgrids, from the tags inside each audio file. Rescan ID3 Tags makes Serato read every file in the library again and update its database to match.

Use it when:

• You edited tags in another app. Serato’s advice is to rescan after changing tags in another program, so it picks up the changes.
• The analyzer re-processes tracks you already analyzed. Rescan first, then analyze, and only new tracks get processed.
• You moved or copied your music. After a move, a rescan flags the tracks that are no longer where Serato expects as missing, ready for Relocate Lost Files. See Relocate Lost Files not working.
• You restored or rebuilt the database. A rescan brings the new database in line with the files.

It does not analyze audio, rename files or delete anything. Because your cue points and beatgrids live in the file tags, a rescan reads them back rather than wiping them. On a large library it can take a while, so don’t start one just before a gig.

Reading, analyzing and writing are different jobs

Serato’s analyzer shows its work in three bars. The first is reading tracks. The second builds the waveform overview, checks the file for damage, and works out auto gain, BPM and key. The third is writing tags, which saves that analysis back into the file. Reading tags at launch is the cheap part. A full re-analysis is the slow part, and Serato normally only analyzes tracks that have not been analyzed yet.

One clue worth knowing: if the status bar shows Writing Tags on a file that is not in the analyzer’s list, Serato’s support team says that file may be corrupt. If the analyzer freezes or crashes on a file, see why Serato keeps crashing or freezing.

Why it happens on every launch

• The Music app library is being imported. On a Mac running Serato DJ Pro 4.0.9, Serato’s own log shows it importing the Music app library on every launch while Show iTunes library is on.
• Something else keeps changing the files. Tag editors, library managers, key detection apps and iCloud Music Library all rewrite files, and Serato has to read them again.
• Serato cannot save. On a read-only file or drive, Serato says metadata changes last only for the session, so whatever it worked out is gone the next time it opens.
• The drive is slow. A big library on a spinning USB drive, or on a drive behind a hub, simply takes longer to read.
• The database is out of step. On Serato’s forum, one DJ with 35,000 tracks reported launch dropping from 20 minutes to 30 seconds after rebuilding a damaged database. See how to fix a corrupt Serato database.

Editing tags outside Serato, safely

Three habits prevent most tag trouble. Quit Serato before another app edits your files, so the two never write to the same file at once. Don’t change tags and file names in one pass in another app: Serato warns that doing both without updating its database breaks Relocate Lost Files and orphans the old entries. And run Rescan ID3 Tags afterwards. That applies to every tag editor, including Crate Cleaner’s bulk tag editor.

If the analyzer keeps starting on your whole library, you often only need to analyze a handful of tracks. Crate Cleaner reads the same tags Serato does and lists every track with no BPM or key, so you can drag just those onto Analyze Files instead of forcing a full re-analysis. The scan is read-only and free on your real library.

Try Crate Cleaner free →

FAQ

Is it normal for Serato to read tags when it starts? Yes, some reading at launch is normal, and it takes longer on a big library or a slow USB drive. Reading or re-analyzing the whole library on every launch is not, and usually has a cause you can fix.

Does Rescan ID3 Tags delete my cue points or beatgrids? No. Cues, loops and beatgrids are stored in each file’s tags. A rescan reads them back into Serato’s library rather than removing them.

Why does Serato re-analyze files I already analyzed? Usually because its library is out of step with the files, or it could not save the analysis to a read-only file. Serato’s fix is to stop the analyzer, run Rescan ID3 Tags, then analyze again.

How long does Rescan ID3 Tags take? It depends on library size and drive speed. A few thousand tracks on an internal SSD is quick; tens of thousands on a USB hard drive can take much longer. Let it finish rather than interrupting it.

Why does Serato say Writing Tags on a file it is not analyzing? Serato’s support team says that file may be corrupt. Check it, and replace or re-encode it if it will not play properly.