Can't Find All Applications Packages Group

Does adding a specific Group to the Local Users and Groups Microsoft Management Console (MMC) snap-in work for you?  To Add a new Group just right-click on the Group folder and follow the prompts.

Default local groups
http://technet.microsoft.com/en-us/library/cc771990.aspx

Sorry I didn't get back to this sooner. I tried soon after you answered, but when I hit a wall again, I got frustrated & pushed it all aside. Then I got busy with other things.

I tried again doing what you suggested, but everything's a dead end. In Computer Management, there's no Local Users group listed. Another help page said this is b/c it hasn't been added to the MMC. When I followed the instructions to do so, I got a pop up that said I can't do that with the app in Windows 8.1, rather I have to use the user accounts in Control Panel. I already have administrator access, so I don't see anything I can change in user accounts.

I tried creating a second account with admin access, but in that account I have the same problem, plus the apps there have "error" listed under them & they claim the apps could not be installed.

Before posting my original question, I Refreshed my system, but to no avail. Is my only option going to be to Reset?

Maybe the Local User and Groups MMC is only available in "PRO" versions of Windows 8.1.  What version do you have?

Local Users And Groups
http://social.technet.microsoft.com/Forums/windows/en-US/1af67021-f23d-4fdb-b7b2-84b73437ec6b/local-users-and-groups

See if this works for non "PRO" versions?

How do I modify user groups in Windows 8?
http://superuser.com/questions/511885/how-do-i-modify-user-groups-in-windows-8

It's non-Pro. Windows 8.1 Core.

I tried the command prompt suggestion, but it only confirmed that my username is already in the administrators group.

I thought you were trying to Add the "All Applications Packages" User to the list of Users in Groups?

"The "All Application Packages" group (a well known group with a predefined SID) must have specific access to certain locations of the registry and file system for Modern Apps to function properly".

Win8: App: Modern: Apps fail to start if default registry or file permissions modified
http://support.microsoft.com/kb/2798317/en-au

Yes, that is what I need to do, but I can't. My original post shows the list of steps your link (http://support.microsoft.com/kb/2798317/en-au) was taking me through. When I reached the last bullet point shown in my post, I can go no further b/c All Applications Packages group is nowhere to be found, therefore I cannot give that group access to anything. The group doesn't exist.

I need to know how to recreate the group.

Did this link, posted earlier, not give you that opportunity in non PRO versions?  You have to create the Group before you can Add it as a User.

How do I modify user groups in Windows 8?
http://superuser.com/questions/511885/how-do-i-modify-user-groups-in-windows-8

It might be something along this command according to that link.

net localgroup All Applications Packages /add

Doing that results in the command prompt saying:

"System error 1376 has occurred. The specified local group does not exist."

Doing that results in the command prompt saying:

"System error 1376 has occurred. The specified local group does not exist."

See if adding quotes where there are spaces makes any difference?  Make sure the Command Prompt is "Elevated" by selecting an Administrator Command Prompt.

net localgroup "All Applications Packages" /add

Also try

To see other options, type:

net help localgroup
https://www.google.com.au/search?q=System+error+1376&sourceid=ie7&rls=com.microsoft:en-AU:IE-Address&ie=&oe=&gfe_rd=ctrl&ei=GUArU-joI6aN8Qedu4HIAQ&gws_rd=cr
Err Msg: System Error 1376 Has Occurred
http://webcache.googleusercontent.com/search?q=cache:kTyf7Xl9jOkJ:support.microsoft.com/kb/119865+&cd=1&hl=en&ct=clnk&gl=au