This installation package could not be opened.Verify that the package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer package.

If you have tried to install as Admin, etc. and that has not worked, someone else may have a different suggestion for you.

Cheers.

I'm using Windows 8.1 and trying to install a new program and keep getting the error:  

"This installation package could not be opened. Verify that the package exists and that you can access it, or contact the application vendor to verify that this is a valid Windows Installer package".

I contacted the vendor who suggested changing user ownership (details below) but this didn't seem to work as I didn't have an owner tab. Any suggestions?

1. Right click on the file or directory. 
2. Click on “Properties” on the right click menu. 
3. Click on “Security” tab. 
4. Click on “Advanced” button at the bottom. 
5. In Advanced Security Dialog window, click on “Owner” tab. 
6. Here you will be able to see current owner (i.e. Trusted Installer). 
7. To take ownership of the object, click on the Edit button. Give permission to UAC. Then highlight the user name in the “Change owner to” box that you want to assign as the owner for the object. Click “OK” to finish the process. 
8. Back in Advanced Security Settings window, you will see the current owner has changed to the user you just selected. 
9. Click “OK” button to exit this window. 
10. Click “OK” again to exit completely from the Properties window. 
11. Repeat step 1 to 4 to open the object’s Properties window again. 
12. Back in object’s Properties window, click on Edit button, and confirm the UAC elevation request. 
13. Highlight the Administrators in the “Group or user names” box. If the user ID or group that you want to manage the permissions for the object doesn’t exist, click on “Add” button, and type in the user name or group name desired into the “Enter object names to select (Can use Everyone as user Name)” box, and finish off by clicking on “OK”. 
14. In the Permissions for Administrators box below (or any other user name or group name you chose), click on “Full Control” under the “Allow” column to assign full access rights control permissions to Administrators group.

Hi,

It always helps us to help you if you tell us what these "secret" programs are named

See if this assists you.

1. Are you installing that Program as the Admin.

Right click on the setup.exe or install.exe > select Run as Administrator.

2. If it is not Compatible, follow these steps:

"Make older programs compatible with this version of Windows"

http://windows.microsoft.com/en-us/windows-8/older-programs-compatible-version-windows

3. "Get your apps and devices working in Windows 8.1"

http://windows.microsoft.com/en-us/windows-8/get-apps-devices-working

Cheers.

Thanks Bill,  The program is spotflux. 

Unfortunately neither of these options seem to have worked.  I tried running the program in compatibility mode in every version of windows from windows 95 to windows 8 but it didn't make any difference.  All of my action center items are up to date.  If you have any other solutions would be very grateful for them.