Samba (CIFS) mount error(9): Bad file descriptor

Edit: someone from the community has noticed that official update fixing the problem has been released; this link provides a solution:

Microsoft released the Update KB4487345 to fix the issue:

This update resolves the issue where local users who are part of the local “Administrators“ group may not be able to remotely access shares on Windows 7 SP1 and Windows Server 2008 R2 machines after installing the January 8th, 2019 security updates. This does not affect domain accounts in the local "Administrators" group.

So download and install the update by doing a double click on the msu file.