Please refer the below link for troubleshooting the above issue.
Also, you can correct the Permission for Adobe folders mentioned below location can also fix this issue.
Let us know if that helps.
The first solution was not possible. I cannot enter Lightroom to check for updates.
The second solution does not have a solution for LR6.
I uninstalled and then reinstalled LR6 and got the same errors.
I can't do solution #4 as I cannot open LR.
I have no Nik plug-ins.
#6 is N/A, so far as I can tell - again, I cannot open LR.
I need to make a correction - my OS is 10.11.1, NOT 10.10 - my error - does that change anything?
I got it to work - many thanks!