[doroth2]

I have 4 GB ram and 320 GB free in the hard drive. Adobe recommends 8 GB ram, but says 2 is sufficient, and I'm running Mac OS 10.11 (and a legal copy of Lightroom).

Go to preferences and look under the performance tab. If you see a check box for "use graphics processor" uncheck it, restart Lightroom and see if that changes anything.

Just did this.

c) Zap your PRAM:
Here’s how to reset your PRAM:
Shut down your machine. Yes, all the way down, not sleep or logging out.
Press the power button and then press command-option-p-r. You have to make sure you get those keys pressed before the gray screen comes up or it won’t work.
Hold those keys down until your Mac reboots again and you here the startup chime.
Let go of the keys and let your Mac reboot normally.

This is next.

If this doesn't work, call Adobe support. They should help you figure out the problem.

For some reason this didn't ever occur to me. Good idea!

[jatrax]

I have 4 GB ram and 320 GB free in the hard drive. Adobe recommends 8 GB ram, but says 2 is sufficient, and I'm running Mac OS 10.11 (and a legal copy of Lightroom).

I ran 16gb until version 6, now I am running 32gb and still occasionally using it all. I honestly do not know how 8gb would work for me. With 4gb, make sure nothing else is running.

And yes, call Adobe. That will be very frustrating but possibly the only way to get an answer. You could also post on the Lightroom forum, they do monitor that so you might get a faster answer that way. Post your hardware and the problem you are having including any error messages. https://forums.adobe.com/community/lightroom/overview

[Alex645]

I have 4 GB ram and 320 GB free in the hard drive. Adobe recommends 8 GB ram, but says 2 is sufficient, and I'm running Mac OS 10.11 (and a legal copy of Lightroom).

4 GB RAM is minimal, but it should work if you quit your other apps. I think it's an issue with the OS.

I run two computer labs with PS6 and LR6 on a total of 36 Macs. Every year IT wants to update our OS but I've learned from experience that is often more problematic with our software. IT thinks we should get software to match their hardware. As a teacher and a user that's backwards; I need the hardware to support my software.

I did a ton of research last year and read a lot of threads where Mac users were having issues with LR6 and OS 10.11. So I insisted that they leave our OS with Yosemite 10.10.4. Our base Macs all run with 4GB RAM, although with 8+GB I know everything would run faster.

You may want to google for any LR patches for OS 10.11 either on the Adobe or Apple sites. Otherwise, is 'downgrading' to OS 10.10.4 an option for you?

Next July, I will be forced to upgrade to El Capitan 10.11 and that may force me to go to CC which I've been avoiding like the plague.

[RollsUp]

I have 4 GB ram and 320 GB free in the hard drive.

Your MBP unofficially supports 6 GB ram. I've used 6 GB on my early 2008 MBP with LR 6 without either of them crashing. I didn't run any other apps while using LR on it though.

You can also try basic LR troubleshooting.

Looking at Console's crash log would give you an idea on why LR and your Mac is crashing.

Here's a tutorial on reading crash logs.