Windows 10 V1903: Update KB4517389 breaks Edge Browser [Fix]

[German]A brief information for users of Windows 10 version 1903 who suddenly have issues with the Edge browser, which won't launch. It is due to the cumulative update KB4517389, which was released on October 8, 2019. Microsoft is aware of the bug, however, a fix is expected by the end of the month. Within this blog post I outline also some workarounds.

Update KB4517389 for Windows 10 Version 1903

Cumulative Update KB4517389 was released on October 8, 2019 for Windows 10 Version 1903 and Windows Server Version 1903. I reported about it in the blog post Patchday Windows 10-Updates (October 8, 2019). Microsoft's support article states that this cumulative update is intended to improve security for Internet Explorer and Edge browsers.

It is presumably a patch for the vulnerability CVE-2019-1367, which has been patched several times since the end of September 2019 (see also Windows: Vulnerabilities in IE and Defender (09/23/2019)).

Microsoft Edge browser does not start anymore

Since the release of the update, KB4517389 for Windows 10 version 1903, some users suddenly find that the Edge browser can no longer be called. Internet Explorer and other browsers work. Within this Microsoft Answers forum thread users complain massively about malfunctions in the start menu as well as about problems with printing. Within the thread, one user reports also issues with the Edge Browser.

I can confirm that. Besides, Edge does not work anymore. It does not start anymore. Internet Explorer starts and runs.

I´ve i deinstall update KB4517389 everythink works as before.
Apart from VMware 14, which does not work anymore, too.

The issues with the broken Windows shell (Start Menu, Desktop Search and Action Center) were discussed in the blog post Windows 10 October 2019 Patchday (Start menu) issues. Within this blog post I also mentioned that some users complain about an Edge browser that no longer starts. Uninstalling update KB4517389 solves this issue as well. Within the MS Answers forum thread linked above, other users confirm this issue. This reddit.com post also mentions the Edge malfunction explicitly.

Just recently installed Windows 10 on my SSD. I used an old iso from around 2015. Windows worked flawlessly with that old version but then I decided to update my windows. After installing all the newest updates my browsers stopped working. Edge, Chrome, even the steam browser. I've downloaded all updates, re-installed the updates and chrome but no change. The only way to get chrome to work is if I run in admin mode. There's no option for that in Edge however.

Even when Chrome is running, it doesn't have an icon in the taskbar. If I try to open edge it pops up for a second then the window disappears. I've tried repairing Edge that didn't do anything.

Does anyone know how to fix this? I don't have any anti-virus aside from windows defender and the only apps installed are steam and origin. It's an almost clean install of windows but I'm still having issues with Edge.

Even the Chrome browser has malfunctions, no icon for the window of the running browser is displayed in the taskbar. Also within my German blog a user has left a comment on a broken Edge-Browser. A second user confirms this in this comment here on my  blog. But it doesn't seem to affect many users.  

Microsoft confirms the Edge issue

I've had escalated the start menu issues within this MS Answers forum thread and asked to forward it to Microsoft's developers. For the start menu issue there was a feedback from a Microsoft employee that this was known and that they were working on a fix for the end of October 2019.

We are aware of this issue and estimate a resolution to be released in late October.

However, it wasn't clear to me which bugs were meant exactly (although the Microsoft developers knew my blog post where the Edge issue has been mentioned as well). Now I came across a second forum thread at Microsoft Answers where issues with Edge are mentioned.

Edge doesn't work

After installing KB4517389 today can't open Edge. Tried rebooting. Tried uninstalling update (then it worked). Reinstalled update and Edge won't open. Tried reset and still won't work. All other browsers work including internet explorer.

There only uninstalling update KB4517389 fixed the broke Edge browser. Microsoft employee PaulSey has also posted the following answer within the MS Answers forum thread:

We are aware of this issue and estimate a resolution to be released in late October.

So we man have a fix till the end of this month. But what's in the mean time? Is there are workaround for affected users?

A possible fix

First it was a suspicion from me, that I posted within the German version of this blog post. For the start menu/shell issue, I had published a workaround to fix start menu issues in the blog post Windows 10: Fixes for October 2019 (start menu) issues. This workaround will replace the broken/missing ActivationStore.dat file in the appdata folder of broken packages. So my idea was to ask affected users (I couldn't test this, because my test system wasn't affected) to check in the Edge directory of the path: 

C:\programdata\Microsoft\Windows\AppRepository\Packages\

for a missing file ActivationStore.dat. Maybe there would be a chance to copy an old edition of this file to the folder an repair the Edge browser. Shortly afterward I received this German comment from Peter V., who wrote, that the file was missing. He was able to copy the missing file ActivationStore.dat from folder:

Microsoft.MicrosoftEdge_44.17763.1.0_neutral__8wekyb3d8bbwe

to

Microsoft.MicrosoftEdge_44.18362.387.0_neutral__8wekyb3d8bbwe

within the path mentioned above. If Edge couldn't be launched using the taskbar's icon, a broken ShellExperienceHost may be the reason. German blog reader W10Tester left here such a comment. In this case, my workaround from the blog post Windows 10: Fixes for October 2019 (start menu) issues will help.

Note: According to this German comment system adaptations using W10Privacy or similar tools could be the trigger for all these issues.

Similar articles:
Microsoft Office Patchday (1. Oktober 2019)
Microsoft Security Update Summary (October 8, 2019)
Patchday: Updates for Windows 7/8.1/Server (Oct. 8, 2019)
Patchday Windows 10-Updates (October 8, 2019)
Patchday Microsoft Office Updates (October 8, 2019)
Windows 10: Fixes for October 2019 (start menu) issues