Windows 10: Windows Store Update App Number Incorrect

Strangely enough, that issue came back to haunt me again, a day or so ago, but I was too busy to worry about it.
Once again, that 'update indicator' showed as if there was an update, but nothing showed up.
However, this evening, as I opened the store, it showed another update - and a moment later it turned out to be the Windows Mail app update. Now the 'update indicator' icon is gone. *really

It's bugging me too, and I was just thinking of a way to troubleshoot further.
A few months ago, I was working an an old Windows SBS 2011 server with Exchange 2010 & Sharepoint services galore.
There was a very nagging issue that I was finally able to narrow down by using a couple of free tools.
The reason I'm mentioning this is because this is one of those nagging things, which is not being very forthcoming, both from a logging perspective (like a lack of errors in the event viewer), and yet a recurring virtual middle finger.
So, here's how I plan to dig deeper -
First, download the free sysinternal tool called ProcMon: Process Monitor - Windows Sysinternals | Microsoft Docs
I use that tool to investigate exactly what the Windows store is doing, what registry hives it's looking for, etc.
I've used this tool in the past to determine that a process was searching for a registry hive that did not exist.
I found out that it did not exist due to an issue with the account I was using (one of three service accounts in SharePoint) was the culprit, because after it became corrupt, it was unable to create a file and save the file, thus not generating the trigger in the registry hive.
I'm wondering if the Windows store is also doing something similar in nature - whereas the store is searching for a value or another indicator or trigger which tells it was needs updating during the scan of the apps.
Although I'm currently not dealing with the indicator anymore, I can at least see where this process is going.
I'll report my findings tomorrow.
Oh, and hey man - about your "Universal Windows Platform (UWP) universal app" comments - well, to help you to understand what I'm attempting to convey, the UWP platform just means that there should be a uniform experience across the devices. That by no means an indication of any type of closeness to identically written code for multiple devices.
Your windows phone for sure does not have a Windows registry the way a desktop or server will. So, although the same end goals are in mind (the experience), the way in which the Windows store is coded to the different platforms are very different across devices. If you want proof of that, run procmon, and filter down to the processes that are tied to the Windows store. That will show you beyond a doubt, that the Windows store is attempting to do multiple things, in multiple places, many of which don't exist whatsoever on your phone.
However, I do understand your point about explaining that it's happening on more than one device (the windows store update thing). There is definitely something going on .... with the windows store

Thanks again everyone for your replies!

 

Not sure if this matters much, but it's worth mentioning that a few days before I found this thread, I had actually opened a couple of remote sessions with support from Microsoft and observed how they wanted to approach 'fixing' this Windows store issue.
Two of their people failed.
The first tech that connected suggested that I stopped the WuAuServ service, then rename the following folder:
C:\Windows\SoftwareDistribution to C:\Windows\SoftwareDistribution.old
Next, we restarted the services and opened the Windows Store, and the update icon was gone again.
As soon as the Windows store was opened, the folder was regenerated.
I compared the contents with something called "Beyond Compare" and they appeared to be identical.
So, I was pretty happy at that point but right after leaving kind feedback and disconnecting, the issue came back again. A few moments later, I reconnected and attempted to get someone else - who attempted to do the same thing...failed...

 

It's gone for me as if today. Whether it comes back remains to be seen. I noticed in the updates list the number was correct but one app said 'no name'. Weird but I let it update and checked reliability history and it related to 'store experience' which updated. So maybe that's what was lurking behind the scenes. Will report back if it returns

 

Same here today, both on PC and mobile. Interestingly the Surface Pro 4 immediately caught the "unknown name" app and when all available updated, the incorrect number went away. On the PC (which is kept in sleep mode usually) the "unknown name" app did not show and the number remained wrong by one until the PC was restarted, at which time the "unknown name" app appeared as an available Store app. When it updated, the number finally corrected.

 

Well the issue with +1 in the update count is back today (10-25-2017). Anyone else seeing this too?

 

I saw it briefly but it went. Looked in reliability monitor and I think it was ‘store purchase app’ that mysteriously installed in background

 

I've had this problem for a while. It appeared then seemed to clear itself up after a few weeks. Today it is back.

Worth noting that it's doing it across multiple Windows 10 machines. Precisely the same symptoms as above.

Guess it's just a 'wait and see' game, as usual, but another nail in the coffin of my confidence in M$ products. After weeks of calendars and people apps not sync'ing properly, the lure of moving to the Google eco-system, much as that pains me, is growing.

 

regarding store, i changed user profile, logged with new account, changed regedit, ran re-register cmd, reset from setting. used powershell command but yet no luck. some time working another system
please help

 

This happened to me when I updated my mail app, for some reason the store app didn't register that the app was updated and displayed the wrong number.

I had to remove the app with powershell, and typed
Get-AppxPackage *windowscommunicationapps* | Remove-AppxPackage

After, I opened the store and redownloaded the mail app and the issue was solved.
The real challenge is figuring which app is causing this for you...

 

The same thing just happened for me. The Store app updated and the problem is gone (again).

 

Ah thanks for alerting me to that. For me it was just something called store purchase app that updated but I did a check for updates just now and the whole store app updated. Total waste of time, just a change of icon (which looks worse) and name change to Microsoft store. I wish they’d leave the native apps alone, they update (and break) them far too much!