On 2 of my accounts negative keywords go missing. They just disappear from the keyword list without a trace.
?
Added: That's bad news, some keywords are disabled now :((
In the Ad Group view, only a certain number of keywords appear per page, and I am guessing that you have your page set to show fewer than the total number of keywords involved.
At the bottom left of your keyword list (in the Ad Group view) is a tool that allows you to set the number of keywords that you see per page. I'd take a look at that, and make sure the setting is such that you can see all your keywords. Your options are to:
Show (30, 50, 100, 500, or all) rows per page
I am about 98% certain that this is a 'sticky' setting that stays where you put it - until you change it again.
I hope that this turns out to be the issue, because it sure would be simple to fix, if so!
AWA
The techies have looked into it and concluded the -words have been deleted manually by someone with access to the account.
Changed passwords and added some new -words. Now waiting to see what happens. I'll keep in touch.. and find out if and how that could happen...
They also gave a valid explanation for the traceless disappearing: words with 0 impressions are not shown in the deleted keywords list.
The tech team seems to be right. I still don't know who has been deleting the -words or why, but it didn't occur anymore after changing the password so at least it's not a bug in the AdWords system.
Thanks all for your support, especially AWA and the team.
I'll keep you posted if anything shows up - either a new disappearance or an explanation :)