A client certificate downloaded over-the-air, cannot be opened and installed on a BlackBerry Z10 or BlackBerry Q10.

Solution:
A certificate can be opened and installed when it has been imported using a USB cable. 

Use the following steps to get a client certificate installed on the BlackBerry Z10 or Q10:

1. To import the certificate using a USB connection, connect your BlackBerry device to your computer using a USB cable. If necessary, on your computer, enter your device password.
2. On your device, swipe down from the top of the home screen.
3. Tap Settings > About.
4. In the drop-down list, tap Network.
5. In the USB section, make note of the IPv4 address.
6. On your computer, navigate to and copy a certificate file.
   • If your computer uses a Windows operating system, in a Run command, type the IPv4 address of the BlackBerry in the following format: \\xx.xxx.xxx.xxx.
   • If your computer uses a Mac operating system, select Go > Connect to Server. Type the IPv4 address of the BlackBerry in the following format: smb://xx.xxx.xxx.xxx.
7. Open the certs folder. If necessary, enter the username and storage access password.
8. Paste the certificate into the certs folder.
9. On your device, tap > Security and Privacy > Certificates > Import.
10. Select the Class of certificate (Either Personal Trusted CA or Personal Client)
11. Select the certificate stores to import the certificate into
12. Press Next
13. Select the certificate to import and select Import
14. Enter the password associated with the certificate if required

B11092