UPDATE: Doesn’t happen on a fresh install with no plugins – so looks like a clash. Bummer – that’ll be fun finding out which one. 🙂
That’s quite strange, as the third argument for preg_match_all is optional is all PHP versions I know. What PHP version are you using?
Thanks.
Phpinfo shows it was 5.2.17 – which seems at odds with my server settings which show 5.4.
I’ve now edited the .htaccess file to force 5.4.35, and things are now working ok again.
After my initial post, I checked some other installs where it had been previously been ok and to which no new plugins had been added – but they too had the same error.
I don’t pretend to understand much of this stuff, but it seems the change of php version is the solution – and this may be related to a recent upgrade to my server by my host.
Thanks for the additional information! It appears that the third argument for preg_match_all was required in some older versions of PHP. To ensure this doesn’t yield an error in Admin Columns, the issue will be fixed in the next Admin Columns release.