Windows 8.1 slow after flash update KB4561600

[German]A blog German reader informed me about an interesting observation in connection with the flash update KB4561600 under Windows 8.1. After the monthly patchday his system was extremely slow. After some searching he found the root cause and a fix.


Normally the Adobe Flash Player should be available in Windows 8.1 and should be updated automatically via Windows Update. I had written something about this in the German article Windows 10: Adobe Flash entfernen. But somehow blog reader Heiko T. must have uninstalled the Adobe Flash Player under Windows 8.1.

System after August 2020 Patchday slow

A few  days ago I received an email from blog reader Heiko T. in which he shared one of his observations under a Windows 8.1 system and offered me to post the info here in the blog (thanks for that).

Dear Mr. Born,

Your blog has often helped me when I was helpless in front of a strange phenomenon in of a Windows installation. For my problem I just solved, I have, however, besides a few somewhat helpful hints in the whole net found nothing. I allow therefore, to tell you the problem and solution – for possible use in the blog and maybe to help other users or admins.

The reader suspects that the problem probably started in July 2020, under the operating system Windows 8.1 (64
bit, maybe even 32 bit) occurs. Heiko wrote about this:

Since this operating system is not (any longer) so common, also the problem rarely occurs – especially since there must be another boundary condition, see below – but, who knows…

Blog-reader Heiko T. then told me his observations under a Windows 8.1 system, which suddenly was extremely slow after the patchday. He describes the symptoms and what he found out quickly like this:

The computer is slow and nearly unusable. The reason will soon become clear: Updates were installed, it must be rebooted. The boot process remains at the “magic 30%”, then reboots correctly and remains at a later location, in “my” case at 87%.

After 10 minutes, it goes up to 98%, and then a screen appears of the format “BSoDv2” – a “blue screen of disease” with the font “We couldn’t complete the updates Undoing changes don’t turn off your computer” 

After about 30(!) minutes (now really that long) this is done, the computer reboots, and the same thing starts all over again.

I didn’t know a BSoDv2 yet – but I’ve already seen the blue screen when setting up updates including their error messages here.


The reason for this behavior

Heiko then took a closer look at the system and found that various updates had been installed after the August 2020 patchday. Among these updates was an update of the Adobe Flash Player (Update KB4561600 from June 2020). He wrote about it:

Anamnesis: In the list of recently installed updates KB4561600 must appear as failed installation. Only then probably THIS error is present.

So Windows Update failed to install this Flash Player update successfully on Windows 8.1. Heiko suggests the following steps as therapy for troubleshooting:

1) Switch off (automatic) updates, reboot.
2) Install the Adobe Flash Player from the Adobe website
3) Switch on updates again.
4) Request and install updates.
5) Uninstall Adobe Flash Player.

I’m a bit suspicious, because the Adobe Flash Player should be installed by default – at least on my Windows 8.1 system the Flash player is present – and is updated via Windows Update from Microsoft. But the blog reader wrote me that it was not available on his system. Then Heiko describes the situation like this:

Obviously the update KB4561600 installs regardless of whether the Flashplayer is present at all.

If the file replacement list is processed after the reboot, the instruction to install a faulty file in the (non-existent) player installation leads to
replace, to an update error.

Sometimes this is visualized by 0x800???????? error, sometimes not. In any case, the error number (or the associated text) is not very helpful in my eyes. The update is mandatory – so you can’t “fiddle around” with it.

Under Windows 8.1 it should be possible to hide the updates and thus exclude them from the installation. Anyway, the blog reader writes: That’s it – and made me sweat for many hours. It’s silly how you can catch consequential errors like that.

The whole subject of Adobe Flash Player will be history by the end of 2020 anyway. Because Adobe has discontinued support for the Flash Player and Microsoft has already started to deactivate the player in the browser (see following article links).

Similar articles:
How to disable Adobe Flash Player in Windows 8, 8.1, 10
Windows 10: Adobe Flash entfernen
Fake News: Flash is dead? No it’s fading out is planned 2020
Adobe Flash: End-of-Live date again announced
Microsoft: Flash in Browser will be removed end of 2020!


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3 Responses to Windows 8.1 slow after flash update KB4561600

  1. Chris Pugson says:

    My thanks to all concerned for this important clue to the solution of the mess which is Windows 8.1 updates. The valuable information I receive from this website is indispensable.

  2. Deb says:

    I received notification that Adobe was no longer supporting Flash and said to uninstall it, which I did a few days ago. Since then I have had awful problems with websites and images loading, either taking a long time or not at all. I’m wondering if the problems are related to me removing Flash Player (despite following instructions to do so). I also use Windows 8.1 64bit. I’m not very techy and would really appreciate any thoughts on the matter. Regards, Deb.

    • guenni says:

      It may be related to the uninstall of Flash – but I’m not the expert on that. Which browser do you use? Perhaps installing Chrome for test will show you, if it’s machine related or browser related.

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