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.
par-in%AppData%\Local\Temp\and try again. – moewe Oct 22 '18 at 19:00