P: Won't start. Ask to change permission of folders, but that doesn't solve.

I just did another experiment. I revoked all access to my entire home folder "/" by everyone. Only me has read/write access to my home folder. My default group ('staff') has read only access. Lr launches just fine.

So it seems that when the account permission is setup properly, there is absolutely no need to grant r/w permission to the entire world in order for Lightroom to work correctly.

There must be something else going on that machine. In my setup, only me have read/write access to my entire home folder "~/", all others just have read only access. And Lr just works fine.

OK-here is a working solution from Adobe forums - but you won ́t like it:

you can try to open the complete Users/library/application support/Adobe
folder to read write for everybody and apply that to all subfolders. I did and it still didnt work.
Only when I did this to the whole library, Lightroom would start..........

Here my reply to the adobe forum


"......And indeed - when I now open up the complete user library with all subfolders (!!!!) to read and write for everybody, Lightroom will start !

I have tried to keep it on a lower level and worked my way up through the folders , but unless the whole user library folder is unprotected , the software won ́t start.

 Completely Unacceptable - this is madness ! A complete security breach. If this is the only way to run the Adobe CC suite now, I will quit and use something else.

 Because this will mean anyone in a shared network, lan or wifi or as a guest on my computer will now be able to access the whole user library with all data !

 Has Adobe gone nuts ? I expect a corrected version that behaves as the 2015.4 before.
I will wait for some days, and if there is no immediate update, I will cancel my subscription !

 Is this due to the NSA madness ? USA going berserk ? Well, if this is the case, Dear Adobe - forget your business."

and this is the polite version

Hi Victoria - I think Jeff is referring to my experience.  I actually restored the whole of Lightroom from a time machine backup from the previous day (not just the catalogue file).  That worked perfectly - it reset Lightroom as previous version and opened as normal with access to catalogue and all presets/settings intact.  

However Creative Cloud now thinks my software is up to date when it isn't.  I wanted to try and install v5 again and I can't - it doesn't even work when I download the standalone update from Adobe.

24hrs ago my lightroom cc worked, I updated it and nothing else, now it will not run just the permissions error. All this rubbish about not shooting the messenger and blaming the os is just an excuse. Adobe sort your buggy update! It has EVERYTHING to do with the subscription i am paying for as the software i need to run today will not work.

Hi Simon. Yes. I even tried  all of this first with the installed software and a restart and then without installed  software and a restart and a fresh install immediately after boot. It ́s not catching on. There is no communication from this point onward.
I have even tried to rename the SLcache and SLstore and did the same thing to maybe get it catching on. Nada.
and frankly the logic pretty much  tells me that as the only new piece of software that arrived on my machine was the Update and the former version did not have any permission problems when I last ran it before I updated, it sounds as if the 2015.5 LR code has some serious flaw.
Especially as 2015.5 Bridge and Photoshop don ́t have any of these problems, probably using the same or a very similar certification structure.

Ok. I guess I possibly underestimated your Mac experiences :-). We want to learn more about your particular situation.

So you set up another OS account with admin privilege and run Lr 6.5/2015.5 from that brand new user account and it still does not work for you (meaning the permission warning dialog still pops up on launch). Is that right?

Yes. I am an Apple certified trainer Simon. I found the Library. 🙂
Lightroom CC 2015.5 doesn ́t see the permissions altough they are there.
I am pretty sure this is a showstopper bug in the program.
And as far as you can see here in the letters and also on Adobe forums,it doesn ́t matter which OSX is running, it seems to happen anywhere. So as much as I am careful about 10.11.x this is not the OS.

@1715680 Did you apply the permission changes to the enclosed items as described https://helpx.adobe.com/lightroom/kb/lightroom-cc-2015-4-lightroom-6-4-crashes-on-launch.html?  Are you able to get to the right folders? The user Library file is hidden by default on Mac OS X 10.7 and later. For temporary access to the user Library file, press Option and choose Go > Library in the Finder.

I run OSX 10.10.5 (by good reasons) and have the exact same problem.
Until the Update the 2015.4 version was working perfectly. Bridge and Photoshop both work fine after the update. But Lightroom denies the permissions altough they are all set properly. It simply doesn ́t see them right. I tried to remove the permissions and reset them with Info, with terminal and even as another ADMIN. I uninstalled it 3 times reinstalled did the permission settings with LR installed or uninstalled, with reboots after installation.......... all to no result.

This is a program bug. Sorry.