OfficeBackgroundTaskHandlerRegistration flashes a window every hour

This was driving me insane, it took me forever to figure out it was the office background updater doing this, it took focus away from any program I was running, including games that would crash every ¤%"#% time, and at the same exact time code,  HH:MM:SS XX:28:38 Every hour, at exactly 28 minutes and 38 seconds it would crash games, and take away focus from programs, flashing a CMD window for .5 of a second. I was getting more and more paranoid, running one antivirus program after another, tearing my software to bits, installing process monitoring programs, I finally nailed the ¤#"#%"%&. WHY IN GOD*S GREEN EARTH WAS THERE NO MENTION OF THIS IN THE EVENT VIEWER, ANYWHERE?? 

Also I just became an office insider, like 10 minutes ago because it says the latest update is supposed to fix this.  I've been plagued with this for at least 1 week

This is not exclusively an Office Insider programme problem.  It is utter nonsense to claim that it is. I have the latest Creator Build, including all updates, installed on two Win 10 64 bit machines.  One is an Asus Laptop, the other is self built desktop PC.  Both are showing this annoying officebackgroundtaskhandler.exe CMD dialogue pop up every hour.

MS should stop trying to blame it on its Insider Program and get it sorted.

And it's even worse for Office, since the production ring receives updates monthly, increasing the risk that some bug, like this one, will reach production.

You are right on with that!  I'm on a production version of Office Home and Student 2016 which was just updated to Version 1704 - 8067.2115.  Now I suddenly have this problem.

Before finding this thread, I posted this.

This issue is fixed starting with build 16.0.8201.2025 which is now available as the latest update for those participating in the Office Insiders Slow program. It will be included in a future update for those not participating in Insiders.

For more information on joining Office Insiders see the Office Insider page.

Thank you everyone for reporting this issue!

Microsoft seems to ignore Insider feedback and insists on using the production ring as beta testers as well. That's also the reason I left the Windows insider program last summer. Insider feedback being ignored for months and bugs being released to production even after countless insider complaints.

And it's even worse for Office, since the production ring receives updates monthly, increasing the risk that some bug, like this one, will reach production. So, I decided to switched to the Office deferred channel (Current Branch for Business), like I already did for Windows. This way I will receive better tested Office updates every 4 months, instead of monthly.

Doing that for Windows is easy, you just enable the flag in Windows Update settings to defer feature updates.

But it's way more complicated for Office. First you need to install some custom policy templates from here: https://www.microsoft.com/en-us/download/details.aspx?id=49030

Of course, the installer doesn't install the templates, that would be too easy. It just unpacks them somewhere, and you have to manually copy the admx files to C:\Windows\PolicyDefinitions. Then you need to use gpedit.exe -> Computer Configuration -> Administrative Templates -> Microsoft Office 2016 (Machine) -> Updates -> Update Channel -> Double Click -> Check "Enabled", Set "Channel identifier" to "Deferred" -> OK.

As a gamer, being able to play my full screen multiplayer games in peace, without popups, automatic reboots and other annoyances is getting harder and harder. I also had to use group policies to prevent automatic reboots. And it's a good thing I'm not paranoid about privacy, and I'm fine with sending telemetry to Microsoft, because completely controlling that seems just as difficult.

It's sad that now gamers almost need some Windows Administrator training to be able to control what their PCs do.