[Tex/LaTex] Updating MiKTeX leads to error in biber version 2.7 and biblatex version 3.7

biberbiblatexmiktexupdate

I just updated my MiKTeX package and in doing so, I started getting two strange errors repeated over and over. I'm running Windows 10.
The errors are as follows:

Package xkeyval Error: family_i' undefined in familiesblx@opt@namepart'. \newpage
Package xkeyval Error: given_i' undefined in familiesblx@opt@namepart'. \newpage

The errors comes, stacked, on the line after \printbibliography.
After the update, I've been, unsuccessfully, running Biber version 2.7 and biblatex version 3.7, and neither is included in biber compatibility matrix.

Is anyone else having this problem, and if so, how did you solve it?

I don't have a MWE because the error started after I updated my packages, and even other documents that were working before the update gives the same error.
I updated MiKTeX as both user and admin, and I cleared the C:\...\AppData\Roaming\MiKTeX\ folder. MiKTeX recreates the repository successfully but the error remains.

PS: I haven't been able to find this error on stackexchange yet, but if it is a duplicate please close it and point me in the right direction.

Edit: I call biblatex with the following line:

\usepackage[maxcitenames=2, citestyle=authoryear,%
bibstyle = authoryear, maxbibnames=2,%
backend=biber, hyperref=true]{biblatex}

Best Answer

When biber or biblatex is updated, auxiliary and/or intermediate files from former compilations may contain invalid data for the new version.

Deleting such files with suffixes .aux, .bbl, .bcf, .run.xml, ... removes this data and the source file can be compiled again.

Related Solutions

[Tex/LaTex] Biber error after MiKTeX update

As the problem actually seems linked to the fact that MiKTeX 64-bit doesn't include biber, which is a 32-bit application, you should take a look at the answers to this question. Don't forget to create a Local TeXMF root if you don't already have one.

Added on 09/20/2015:

Since last summer, MiKTeX 64bits repositories have a miktex-bin-biber-x64.tar.lzma file, so the above-mentioned answers are obsolete. Install biber through MiKTeX Package Manager.

[Tex/LaTex] How to install the development version of BibLaTeX (using MiKTeX on Windows)

In summary, this were the required steps on my system:

Create a local texmf tree. The gist is, create the folder C:\localtexmf and a subfolder tex and then run
```
initexmf --register-root=c:\localtexmf
initexmf --update-fndb
```
Open MiKTeX Options and go to the "Roots" tab. Check the "Show MiKTeX-maintained root directories" box. Your local tree should be before "UserInstall".
1. If your local tree is before "UserInstall", you can skip to the next bullet point.
2. If you can use the "Up" button to move your local tree before "UserInstall", then do so.
3. Else, your setup probably looks like this, i.e. "UserInstall" and "UserConfig" point to the same path. In this case, you need to separate "UserInstall" and "UserConfig". To this end, set an environment variable MIKTEX_USERINSTALL that points to the new "UserInstall" path. I chose C:\Users\CL\AppData\Roaming\MiKTeX\2.9\install.
4. Run initexmf --update-fndb --verbose. Now, the local texmf directory should be listed before UserInstall but after UserConfig and UserData.
5. Run kpsewhich --all biblatex.sty. This will probably point to a file in your UserConfig tree (in my case: C:\Users\CL\AppData\Roaming\MiKTeX\2.9\tex\latex\biblatex). I suppose that this should not be the case but is an artifact of separating UserConfig and UserInstall after the fact. Delete that biblatex directory and update FNDB.
Download the development version of BibLaTeX from Sourceforge. Choose the file with the tds.tgz extension (e.g. biblatex-3.7.tds.tgz).
Open the tds.tgz file. It contains a tds.tar file. Copy the contents of the tds.tar file to your local texmf directory:
Run initexmf --update-fndb --verbose and then kpsewhich --all biblatex.sty. This should point to biblatex.sty in your local texmf directory.
Don't forget to use the matching (development) version of biber.

A remark on step 5 under the second bullet point. As the local texmf tree has precedence over UserInstall (if MiKTeX is set up correctly), it is usually not necessary to remove the old/stable version of a package before copying a new version to the local texmf tree. The reason why the biblatex directory needs to be deleted in step 5 is because after separating UserInstall and UserConfig, the files (wrongly?) remain in UserConfig. Packages that are installed after the trees have been separated end up in UserInstall and don't need to be removed manually when another version from the local tree is to be used.

Christian Schenk suggests to move the contents of UserConfig to UserInstall when separating the trees. This should make deleting the biblatex folder obsolete.