In our testing of this issue we also found turning off SIP as a potential solution, however we were reticent to share this since we felt that this “solution” was somewhat inelegant in that it has some security consequences.
On one side of the argument, if you disable SIP you’ll get the same level of protection as you had with OS X versions before El Capitan. But alternatively it could be said that SIP protects against vulnerabilities that did not exist or were unknown previously.
We are continuing to work on a solution to this “Installed but not available..” error issue and we will post when a fix is ready to be released.
Thanks for your patience,