95% of library's Published date randomly changed

[Thinkling]

I am a stickler for saving the Published field date of my files in Calibre (MacOS 26).

Today I noticed something very alarming. About 95% of the files had this field changed to January 29, 2026. This make zero sense, as the vast majority of files predate that...often by years. I have upwards of 13000 files (mostly news/magazine articles).

Any advice as to what happened here, how it can be fixed, and how to avoid in the future. I am aware of the "Edit metadata in bulk" command and can assure you this was not carelessly used.

Thanks in advance.

[BetterRed]

Which version of calibre?
If version 9 when did you install it - date & time if possible?
What formats do you have for the 5% where pubdate did not change?

BR

[theducks]

FILES?
Published is a column in Calibre. The File (creation and modified) dates change with data updates.
Did you ADD/delete a custom column? That affect metadata.opf in all book folders (it updates in background) so you have a Library Recovery ability if the main db gets hosed.

[Thinkling]

Originally Posted by BetterRed

Which version of calibre?
If version 9 when did you install it - date & time if possible?
What formats do you have for the 5% where pubdate did not change?

BR

Thanks for replying. I installed v9.2.1 earlier that day the 6th.

Vast majority that did not change were PDF and EPUB, small numbers of MOBI, AZW, AZW3, and DJVU. Although it seems to me roughly the distribution of the formats anyway.

[Thinkling]

Originally Posted by theducks

FILES?
Published is a column in Calibre. The File (creation and modified) dates change with data updates.
Did you ADD/delete a custom column? That affect metadata.opf in all book folders (it updates in background) so you have a Library Recovery ability if the main db gets hosed.

The last custom column activity I performed was adding a column last ~May. This by itself suggests this is not pertinent, but I'm happy to re-entertain the possibility.

I will probably dig into the Library Recovery option. Thanks for replying.

[theducks]

Just to be clear:
We are talking about the {Published} date column/field?
The only thing I can think is you accidentally did a Bulk Mode metadata update that included more that you intended . (Been there)

Always check the status lines # selected , before executing the bulk update.

[BetterRed]

Originally Posted by Thinkling

Thanks for replying. I installed v9.2.1 earlier that day the 6th.

Vast majority that did not change were PDF and EPUB, small numbers of MOBI, AZW, AZW3, and DJVU. Although it seems to me roughly the distribution of the formats anyway.

Did you install 9.0.0, and when would you have installed it, it was released on "30 Jan, 2026". I think that may be Mumbai time, Pennsylvania lags Mumbai by 10½ hours, so if you were quick off the mark, maybe . . .

FTR - I value Publication Date for the same reason as you… it matters a lot for news/magazine/journal items. I have also installed version 9.x.x (beta and release) and my Publication Dates have not changed.

Which makes me wonder if an optional plugin or third party program is at play… something triggered by a database schema change… version 9.0.0 and subsequent releases do change the database schema for existing libraries.

BR

[Comfy.n]

Mine haven't changed either, but I noticed a time-related oddity about the .msi installer, beginning from 9.2 release. Didn't affect 8.99.12 nor 9.0 nor 9.1, in my perception.

I often get and install new versions very close to release time, but this time I noticed calibre creating files in its installation dir with timestamps that were ahead of the then-current local time.

[Thinkling]

Originally Posted by BetterRed

Did you install 9.0.0, and when would you have installed it, it was released on "30 Jan, 2026". I think that may be Mumbai time, Pennsylvania lags Mumbai by 10½ hours, so if you were quick off the mark, maybe . . .

FTR - I value Publication Date for the same reason as you… it matters a lot for news/magazine/journal items. I have also installed version 9.x.x (beta and release) and my Publication Dates have not changed.

Which makes me wonder if an optional plugin or third party program is at play… something triggered by a database schema change… version 9.0.0 and subsequent releases do change the database schema for existing libraries.

BR

Hmm I don't think I can verify if/when I installed 9.0.0. I probably install about 2/3 of the new versions when I get the update notifications. To my knowledge I never install beta versions, unless (say) X.0.0 versions are betas.

That said, if you're right, that coincidence about the v9 date does seem intriguing. I have maybe half a dozen plugins installed, but IIRC I have never actually used any. Doesn't mean they can't do harm though, I guess.

I greatly appreciate yours and everyone's engagement with my issues on this thread.

[Thinkling]

Originally Posted by theducks

Just to be clear:
We are talking about the {Published} date column/field?
The only thing I can think is you accidentally did a Bulk Mode metadata update that included more that you intended . (Been there)

Always check the status lines # selected , before executing the bulk update.

That is a clear possibility, in the sense that I knew right away it could cause my problem. But to be honest, I am 99.999% sure that didn't happen. Your advice, however, will always be valuable going forward .

[BetterRed]

Fairly easily done though, I just did it with 6 key 'strokes',

Ctrl+A — select all books
E — Edit Metadata in bulk
Alt+U, Alt+U — to get to Published
'=' — to set to Now
Enter — to Commit changes

Even easier if you use a mouse… click into Published when you were aiming for Date, press '=', click OK

There is no "Are you sure" popup.

BR