# Biber 2.11 crashes on biber --version

Whenever I call Biber (even on biber --version or biber --help), I get the following error message (shortened)

The following parameter was passed in the call to DateTime::Format::Builder::Parser::create_single_parser but was not listed in the validation options: regex
at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\ee447f6b.pm line 164.                                                                                                                               DateTime::Format::Builder::Parser::create_single_parser(undef, "params", ARRAY(0x490d620), "length", ARRAY(0x49097d8), "regex", qr(^ (-?\d{4}) - (\d\d) - (\d\d)\x{a}                           )...ux) called at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\ee447f6b.pm line 305                                          BEGIN failed--compilation aborted at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\507a905c.pm line 5.
...
Compilation failed in require at script/biber-MSWIN64 line 17.
BEGIN failed--compilation aborted at script/biber-MSWIN64 line 17.


I'm using MikTex 2.9 on Windows 10, Biber Version 2.11. Uninstalling and reinstalling Biber did not solve the issue. The problem occured today out of the blue, my local biber version was last updated in April.

The only other mention of the issue I found is https://chat.stackexchange.com/transcript/41/2018/6/17/0-24, however, no solution is mentioned.

• How did you install Biber? Delete all folder starting with par- in %AppData%\Local\Temp\ and try again. – moewe Oct 22 at 19:00
• This fixed it. I installed Biber via the Miktex Console. – jaytar Oct 22 at 19:04

A while ago there was an infamous sort of error when running Biber: Biblatex/biber fails with a strange error about missing recode_data.xml file. That error appeared when the cache Biber unpacks on a first run got corrupted. While there have been no complaints about this particular problem since the issue was fixed in the Perl library responsible for the unpacking, PAR::Packer, the message you are getting

The following parameter was passed in the call to DateTime::Format::Builder::Parser::create_single_parser
but was not listed in the validation options: regex
at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\ee447f6b.pm line 164.
DateTime::Format::Builder::Parser::create_single_parser(undef, "params", ARRAY(0x490d620),
"length", ARRAY(0x49097d8), "regex", qr(^ (-?\d{4}) - (\d\d) - (\d\d)\x{a})...ux)
called
at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\ee447f6b.pm line 305
BEGIN failed--compilation aborted
at %AppData%\Local\Temp\par-6a6f6e6174\cache-9d6b46fefde4bd584f892f8159e8daefd64788a3\507a905c.pm line 5.
...


suggests that something might be wrong with the unpacked cache.

Delete the cache directories in %AppData%\Local\Temp\ (they start with par- and a hash) and try again. If biber --cache works without errors it will point you to the exact location of the cache folder.

If you have been using Biber for a long time you may find that there are several cashes in the par-... folders. Usually only one will be in active use, the older ones will have gotten stale. You can safely delete all of the Biber-created caches (even the active one), since they will be recreated when you run Biber the next time (and so it should be, after all the cache is in the temp directory).