Weird "unknown account" with special permissions for C. Should I remove it?

AlterNate37 · 2025-03-09T07:42:30-0400

Hello,

I arrive to this community with a dilemma.
While checking the permissions on my user folders (documents, downloads, pictures etc), I noticed that Music, which is in a separate SSD, had inherited permissions from my previous installation of Windows.
I controlled the permissions of all drives and in C I noticed an "unknown account":

with special permissions:

ChatGPT says:
From the look of that SID—S-1-15-3-something-something—it’s most likely a “capability” or “app package” account that Windows can’t match to a friendly name anymore. In other words, it’s some sort of leftover or special system/app identity that Windows used to recognize, but now shows as “Unknown” because the link to that app or service is broken or unresolvable.
Since it’s on your C:\ (the root OS drive), I’d be a bit cautious. While it may just be an abandoned permission from an uninstalled app, messing with root permissions can sometimes lead to comedic levels of Windows meltdown—where you’re locked out of your own system or some vital process stops working.

What do you think?
Thanx

neves · 2025-03-09T07:56:03-0400

That's a Windows hidden Security account. You can tell by S-1-15-whatever. It's used for background tasks - like Windows Security Updates, automated storage scheduler and such...

Helmut · 2025-03-09T08:33:21-0400

Stop meddling. That I think is one of those special accounts Windows may use for updates, temporary security changes, or something like that.

So much for ChatGPT's nonsense.

AlterNate37 · 2025-03-09T09:05:26-0400

Helmut said:
So much for ChatGPT's nonsense.

I told ChatGPT what you said.
It said: "Ah, the classic "stop meddling" response—nothing like a bit of fearmongering to keep Windows as mysterious as ever."

AlterNate37 · 2025-03-09T09:06:28-0400

neves said:
That's a Windows hidden Security account. You can tell by S-1-15-whatever. It's used for background tasks - like Windows Security Updates, automated storage scheduler and such...

How do I know if it's active or some leftover?
If it's a leftover, does it do harm if it stays there and with permissions?

Fabler2 · 2025-03-09T09:35:32-0400

I've got the same - which I'll leave well alone.

Bree · 2025-03-09T09:42:42-0400

AlterNate37 said:
How do I know if it's active or some leftover?
If it's a leftover, does it do harm if it stays there and with permissions?

It's a Capability SID, we all have some. Do NOT touch! It's required by the system.

Microsoft said:
Capability SIDs uniquely and immutably identify capabilities. In this context, a capability is an unforgeable token of authority that grants a Windows component or a Universal Windows Application access to a resource such as documents, cameras, locations, and so forth. An application that "has" a capability is granted access to the resource that is associated with the capability. An application that "does not have" a capability is denied access to the associated resource.

The most commonly used Capability SID is:
S-1-15-3-1024-1065365936-1281604716-3511738428-1654721687-432734479-3232135806-4053264122-3456934681

Don't delete Capability SIDs from either the registry or file system permissions. Removing a Capability SID from file system permissions or registry permissions might cause a feature or application to function incorrectly. After you remove a Capability SID, you cannot use the UI to add it back.

Some SIDs don't resolve into friendly names - Windows Server

Some security identifiers that you see in access control lists or Security Audit reports don't resolve into friendly names. These might be Capability SIDs.

learn.microsoft.com

Microsoft said:
To get a list of all of the Capability SIDs, follow these steps:

Select Start > Run, and then enter regedt32.exe.

Navigate to the following registry entry: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SecurityManager\CapabilityClasses\AllCachedCapabilities.

Copy the value data and paste it into a text file (or a similar location where you can search the data).

Bree · 2025-03-09T09:55:53-0400

AlterNate37 said:
ChatGPT says:
From the look of that SID—S-1-15-3-something-something—it’s most likely a “capability” or “app package” account....
...messing with root permissions can sometimes lead to comedic levels of Windows meltdown—where you’re locked out of your own system or some vital process stops working.

Welcome to Eleven Forum, by the way.

I see that ChatGPT got close to telling you the same thing....

AlterNate37 · 2025-03-09T10:06:28-0400

Fabler2 said:
I've got the same - which I'll leave well alone.

Did you use StorageExecutive by Crucial?
I used it to try their Momentum Cache on C, so I thought maybe it's that.I ask because yours has the same exact number, so I guess it's the same Capability. I wonder from what...

Bree said:
Welcome to Eleven Forum, by the way.

I see that ChatGPT got close to telling you the same thing....

Thanx

Yeah, you're right, I didn't/don't know what a Capability is, so I didn't even notice that there was a specific hint in those words.
I've set Geepee to have a cynical slightly sarcastic humor, which doesn't work well with technical info apparently. I'll have to update its Memory.

Is there a way to know which Capability exactly? Related to which feature or app?

neves · 2025-03-09T10:08:24-0400

AlterNate37 said:
How do I know if it's active or some leftover?
If it's a leftover, does it do harm if it stays there and with permissions?

I think ChatGPT misunderstood your question - since you didn't use the S-1-15-whatever variables. If you included that - you'd get an answer like the folowing:

"The string "S-1-15-" appears to refer to a Security Identifier (SID) in Windows operating systems. A SID is a unique value used to identify a security principal, such as a user or a group, within a Windows environment.

The "S-1" part of the SID signifies that it is a well-known or standard SID structure. The "15" part could be a specific identifier related to a type of user, group, or system entity within Windows security.

However, "S-1-15-" is not a common or typical SID prefix that directly corresponds to an individual user or group. It might be related to some internal or system-level account or service that is specific to the operating system or a particular version of Windows.

If you're encountering this SID in logs or error messages, it could be related to a service, an account that is dynamically created by Windows, or perhaps a configuration issue that might need further investigation. To resolve it, you can:

Identify the exact SID: Check the full SID, as it may give more insight into the specific security entity.
Use tools like PowerShell: You can use Get-ADUser or Get-ADObject commands (in the case of Active Directory) to query information about a SID.
Windows Event Logs: Look for more information in the Windows Event Logs to see if any events are associated with this SID."

-------------------------

You could always delete/remove it - and see what happens.

AlterNate37 · 2025-03-09T10:20:35-0400

neves said:
I think ChatGPT misunderstood your question - since you didn't use the S-1-15-whatever variables. If you included that - you'd get an answer like the folowing:

Nah, it's just the cynical sarcastic humor setting.
I removed that and replaced it with tech-savvy attentive thorough and it gave me a technical explanation about capability stuff.
I did use the screenshot of the permission though, ChatGPT can read screenshots.

Anyway. Unless there's a way to see what app/component triggered the capability (just to see if I still have that), I'll just forget it.
I suppose that even if it's a leftover of something uninstalled, it won't do any harm if it stays there.

Ah, I missed the end of your reply.
Do you happen to know the PowerShell code to look for that?

neves · 2025-03-09T11:07:17-0400

AlterNate37 said:
Nah, it's just the cynical sarcastic humor setting.
I removed that and replaced it with tech-savvy attentive thorough and it gave me a technical explanation about capability stuff.
I did use the screenshot of the permission though, ChatGPT can read screenshots.

Anyway. Unless there's a way to see what app/component triggered the capability (just to see if I still have that), I'll just forget it.
I suppose that even if it's a leftover of something uninstalled, it won't do any harm if it stays there.

Ah, I missed the end of your reply.
Do you happen to know the PowerShell code to look for that?

Not by memory, but it's easy to find:

Get-ADObject (ActiveDirectory)

Use this topic to help manage Windows and Windows Server technologies with Windows PowerShell.

learn.microsoft.com

Tho, you're overcomplicating things. That's useful if you're using PS remotely - if you have an Active Directory module for PS (pretty sure you don't - since it's not installed by default on a home PS). Thus, above commands won't/shouldn't work - unless you actually install it - which again... why?

Instead, just look for above SID in the registry (using a registry finder app) - and it should point you to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\SecurityManager\CapabilityClasses

PS.ChatGPT is just a tool, can be really useful - but only if you ask smart questions. With humans on the other hand - it leads to dialogues like above

AlterNate37 · 2025-03-09T11:12:42-0400

neves said:
just look for above SID in the registry

I had already done that. With the integrated search function of Regedit.
It did find that string among a long list of other strings but there's no indication whatsoever of what component/app/feature it belongs to.

About the why: just in case that if I have already uninstalled that app it might be inconvenient to leave this leftover.
You know, a bit like registry cleaning, which btw I don't do anymore since ages because I don't trust Ccleaner & Co.

If you say it's no issue even if it's an inactive leftover, I'll leave it over.

garlin · 2025-03-09T11:25:33-0400

AlterNate37 said:
Did you use StorageExecutive by Crucial?
I used it to try their Momentum Cache on C, so I thought maybe it's that.I ask because yours has the same exact number, so I guess it's the same Capability. I wonder from what...

Thanx
Yeah, you're right, I didn't/don't know what a Capability is, so I didn't even notice that there was a specific hint in those words.
I've set Geepee to have a cynical slightly sarcastic humor, which doesn't work well with technical info apparently. I'll have to update its Memory.

Is there a way to know which Capability exactly? Related to which feature or app?

App capability SID's are assigned to either a Windows feature or user-installed app.

S-1-15-3-x1-x2-x3-x4 --> can be translated back to a Windows GUID like {BFA794E4-F964-4FDB-90F6-51056BFE4B44}
S-1-15-3-x1-x2-x3-x4-x5-x6-x7-x8 --> cannot be translated, because it's a SHA256 hash of the App's name

Unless you were checking at the time an app was installed, you probably won't know which app owns the SID. Sometimes you might be lucky and another person claims to have the same SID (or app) installed as you.

AlterNate37 · 2025-03-09T11:51:21-0400

garlin said:
Sometimes you might be lucky and another person claims to have the same SID (or app) installed as you.

Mine is S-1-15-3-65536-1888954469-739942743-1668119174-2468466756-4239452838-1296943325-355587736-700089176
From @Fabler2 screenshot it seems that he has the same.
So, it should be either the same Windows feature or user-installed app. That's why I asked about StorageExecutive.
If anybody finds out, it would be interesting to know where it comes from.
Otherwise I'll just let it be.

neves · 2025-03-09T12:29:54-0400

AlterNate37 said:
I had already done that. With the integrated search function of Regedit.
It did find that string among a long list of other strings but there's no indication whatsoever of what component/app/feature it belongs to.

About the why: just in case that if I have already uninstalled that app it might be inconvenient to leave this leftover.
You know, a bit like registry cleaning, which btw I don't do anymore since ages because I don't trust Ccleaner & Co.

If you say it's no issue even if it's an inactive leftover, I'll leave it over.

It's not a leftover. It's garbage coding - as i've already explained in this topic:

Dism /restorehealth not working

Hello, suddenly Dism /online /cleanup-image /restorehealth is no longer working! - It starts but then gets stuck at 62.3% ... - sfc /scannow works fine ... no problems detected. -Dism checkhealth and scanhealth also work. I checked online with varying results ... no fix or very technical ...

www.elevenforum.com

Here's an official explanation for the "Unknown" naming part: Some SIDs don't resolve into friendly names - Windows Server They know about it - but they don't know how fix it. Windows it's a humongous pile of coding mess. You'll find lots of similar issues ( like hundreds of thousands of empty folders generated randomly in WinSxS - and no, they're not cleaned with command likes like <span>Dism.exe /online /Cleanup-Image /StartComponentCleanup /ResetBase ). But as long as "windows functions" - this issues are not a priority (tho, maybe they don't know how to fix them). Same goes for signing LSA packages or DisrtibutedCOM errors - present even on a newly/fresh installed Windows (as can be seen in Event Viewer). That being said, don't look for issues - when Windows is still running (somehow - even the devs working on it are not entirly shure - why it still works). Supposdly by now (including latest build) - Windows 11 might have close to 100 milions lines of code. So unless they use A.I. - some fixes (for old buried issues) - are like a miracle at this point.

garlin · 2025-03-09T12:56:35-0400

Stop spreading FUD. Capability SID's based on apps are documented. It's a SHA256 hash to prevent collision from different software developers using the same SID by random chance. And it frees MS from being a gatekeeper and assigning them by request.

Raymond Chen is a Principal MS dev, so he's got the inside dirt on why Windows is done a certain way.
What are these SIDs of the form S-1-15-3-xxx?

neves · 2025-03-09T13:23:52-0400

garlin said:
Stop spreading FUD. Capability SID's based on apps are documented. It's a SHA256 hash to prevent collision from different software developers using the same SID by random chance. And it frees MS from being a gatekeeper and assigning them by request.

Raymond Chen is a Principal MS dev, so he's got the inside dirt on why Windows is done a certain way.
What are these SIDs of the form S-1-15-3-xxx?

What are you talking about?!

That's a different context/explanation altogether. He says nothing about the erroneous naming - where "by design" - this Windows generated hidden accounts for app capability SIDs - end-up labeled as "Unknown" - confusing many people who bump into them - thinking it's some kind of security breach. There's thousands of topics all over the internet - questioning this error - and still not resolved to this day. Raymond Chen - explains the meaning (and why/how they are generated) of the generated numbers beyond S-1-15- That doesn't explained why it's labeled as "Account Unknown".

Weird "unknown account" with special permissions for C. Should I remove it?

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