windows 2016

Well, is \0 expected, and if it is, did you try to set --binary-mode as the message suggests?

the issue was because of powershell (see blue screen).

powershell ">" is different from cmd ">"

when run from cmd - everything is ok

wlad, any comments on this?

there is --result-file option in mysqldump that can/shall be used with mysqldump, instead of redirection

I guess there's BOM
will have a look later

does it make sense to teach mysql.exe to understand BOM ? or just close this issue ?

--result-file should not write a BOM. Does it?
I'd prefer some better raw pipe handling in powershell, along the lines of https://github.com/PowerShell/PowerShell/issues/1908.

I'd like to redirect the questions about whether mysql understands UTF16, and question concerning BOMs to bar

"--result-file should not write a BOM. Does it?" - I was talking about powershell

there is a section in MySQL's documentation dedicated to this very topic https://dev.mysql.com/doc/refman/5.7/en/mysqldump.html
about mysqldump and powershell and UTF16.
Let me quote it in full

 Note

A dump made using PowerShell on Windows with output redirection creates a file that has UTF-16 encoding:

shell> mysqldump [options] > dump.sql

However, UTF-16 is not permitted as a connection character set (see Section 10.4, “Connection Character Sets and Collations”), so the dump file will not load correctly. To work around this issue, use the --result-file option, which creates the output in ASCII format:

shell> mysqldump [options] --result-file=dump.sql

it specifically mentions --result-file as a workaround.