MacBook Pro loses access to 1 memory slot upon shutdown or reboot in OS X 10.8.1

Thanks Patricia, I'm glad this is working out for you. As far as my computer goes, it has been reading all 8 gb of RAM no matter how many times I restart, even after running graphic intensive applications (heating the macbook up quite a bit).

Just to add a little to the above tutorial, I would advise loosening all 4 screw by about 1/2 a millimeter. If you look carefully, there are these tiny "gold rods" that stick straight out and retract when you push on them. The screws should not exceed those rod's length.

I have asked some hardware design engineers, and they don't seem surprised that this is happening to my 3 year old beloved macbook pro. The heat is DEFINITELY an issue (see my above post) and hence the new macbook design with soldered ram. But they gave me a bunch reasons, warping circuit board, solder melting and loosening contact, etc. I really have no idea why loosening the screws work aside from the fact that it may allow the circuit board to expand.

I hope this fix is more less definitive until the computer really just dies.

Looking good so far - your advice is the first that I've found that suggests a solution with good reasoning behind it and, so far, looks like solving my problem. *Thank you*.

I have a mid-2009 13" MacBook Pro which has manifested:

• sproadic video corruption - nothing debilitating, just a temporary visual glitch

• Bank 1 of my RAM flaking and refusing to recognise known good memory

• the 'black screen of death' - return to the user login window, sleep the Mac, reawaken to find a black screen that nothing short of a hard reboot will solve

So far, so good…

I've recently had the same problem with my mid-2009 13" MacBook Pro. Top slot works fine, bottom slot doesn't. Often fails to wake from sleep with both slots filled due to detecting/loosing bottom slot after being moved around.

I'll try the fix with loosening the screws this weekend and report back. Makes sense that heat could cause an issue over time. These things run hot. So glad I found this thread. Should save me hours of troubleshooting.

Hi,

I have exactly the same issue - incredible that the Apple support cannot help. Thanks a lot for this solution, seems also to work for me.

Hi

I cannot believe that so many people have had the same issues with the same computers and apple have not made people aware of it. I have taken my computer to 3 "geniuses" and none of them were able to help. They said replace case as it may be magnets, and said it was error in sleep file etc etc.

I have tried to do this and it seemed to work for a day. The next day.... as i had ordered new ram before i found your post, i upgraded to 2 new 4gb ram so i switched them. When i first switched on it recognised all 8gb but now it is only recognising 4 and it has done a shutdown after waking from sleep mode twice. Do other peoples also do shutdowns / start up when they open up after sleep?

Just after any insights as to what i may have done wrong.... Do you think the screws may be too loose? or not enough? Any advice from others that have succeeded would be appreciated just to reduce my trial and error time!

I am so glad for this post and effort mad eby people as i was searching apple for what computer to replace my beloved 17" with when i looked this up, will hopefully delay the expentiture for a while.

I have tried numerous fixes, many of which temporarily got my full RAM back online. Finally, I tried this fix (loosening the screws just a tad), and I have had no issues for almost two months. Thank you for this!

MacBookPro5,1

Intel Core 2 Duo – 2.53 GHz

4 GB RAM

I tried quadturbo's method and it didn't work work ... My current guess is, the RAM slot degraded as Quadturbo's analysis, and cannot align the RAM to a correct contact positions. To be specific, take a look at my illustration:

Notice that the two clips on the left and right are used to hold the rams in a horizontal position, otherwise they will bend upwards. I took a close look at those clips and found that the plastic wore out and cannot hold them as original. I don't have great ways to fix them, so I just cropped some papers and insert them between the RAMs and the back edges on the body, hoping they can help tucking the RAMs.

As far as I can see, this fix the issue. Not sure if it is the real cause, just my two cents.

Thanks, dude. I just ordered a new laptop and I came across this thread trying to find out what to do with my MBP while I wait for my new one. I loosened three ****ing screws (the fourth was stubborn and I stripped it) and I'm back to 8GB. You're the man, quadturbo. Thinking about cancelling my order, but hard to say no to new hardware.

quadturbo wrote:

I believe I have found a DEFINITIVE solution to an identifiable problem. I have a Macbook Pro 13" 2010, with 8 gb ram. In the last 6 months, I have had Bank 1 (4 gb) disappearing on me intermittently. In the last two months, I had consistent loss of 4 gb of ram, especially after restart. When I start cold (after 24 hours), it recognizes 8 gb, but if I restart, it recognizes only 4 gb. I would stick the macbook in the freezer for 10 min. Of course, I get 8 gb.

So what the ****?

I have gone through every thread google has to offer. No solution, except that the best explanation was that circuit board was getting old. It explains why Apple created new vents for the new Macbooks. I also believe they soldered in the ram for this exact reason.

So I got sick of it and opened up the macbook, unscrewed, removed, cleaned out the fan, unscrewed the circuit board removed the Ram. I even unscrewed the 4 screws around the plastic RAM holder. I cleaned everything out with 91% isopropyl alcohol and everything inside the RAM holder and the ram itself.

I tested each RAM in each slot alone and carefully turned the computer on. 4 gb as expected. Both banks worked. Both RAM functioned fine alone in each of the banks.

So what the ****?

I popped both back in.....8 gb. Restarted it. 8 gb. I did this 10 x. Every time 8gb.

So I thought it was because I did a great "cleaning" job. I screwed everything back in, circuit board, RAM "holder", etc. Restarted....7.75 gb. !?

Restarted again.... 4gb?! DId this 10x, 4 gb.

What the ****?

I opened everything and LOOSENED the four screws around the Ram HOLDER.....

8 gb ever since!

I believe with time, the awesome heat from the macbook pro eventually warps the circuit board. My macbook was just under 3 years old and started to have this problem. The four screws holding the ram holder in start to tighten up with heat and somehow it does not recognize one bank. That's why when I freeze the macbook, it gets the other bank back. By loosening the screws, it allows the circuitboard expansion with heat.

Anyways, I hope that helps.

Thanks quadturbo! If you still check this thread, has your fix lasted?

I posted an article to my site detailing the fix you suggested to hopefully help others:

https://people.cam.cornell.edu/~zc227/extras/mid2009mbp_RAM.html

I'm still following this thread and yes the fix has lasted. Skimnc, great write up, I'm glad this helped alot of people. I gave my mac to my sibling who games on it (heat galore). After restarting, it still reads all the RAM!

I really like iveney's explanation and his success confirms my theory of the board warping and distorting the contacts.

As for me, I moved onto a Retina 15" 16 gb. I liked the fact that they solder their ram in. And its kind of slimy that Apple probably internally knows about this problem. The retina is very solid.

Thanks skimnc for the dedicated page. I also have a temporary fix and it seems the problem is resolved. I wrote a blog post on this, with some pics:

http://blog.ivansiu.com/blog/2014/05/28/fix-mid-2009-mbp-ram-not-recognized-issu e/

For those of you that still want to stick to the old MBP, the fix shall last for a while. But I do recomend you backup all the files and prepare to migrate some day soon.

Thanks to all the posters on here. I just wanted to share my related story.

I had the same issue, and fixed it by loosening the screws. Then that stopped working, so I retightened them. After a while I had to loosen them again...and on and on. Then I started getting freezes and discolored screen locks just from tapping my laptop. Reading online I was wondering if maybe this was my HDD connections and I needed new cables.

So I opened up the back with the laptop running (shame on me, right?), and tapped around on various components trying to duplicate what would happen when it was all closed up (if I would even tap on the desk too hard the thing would lock up and require reboot). I tapped on all the cables. Nothing. Then I tapped on the RAM bracket, and everything went pink and blue and locked up. So I loosed the RAM bracket screws, removed the RAM, retightened the screws, and replaced the RAM and rebooted. With the back still open, I logged in and saw all the ram (8GB) present. Then I tapped the RAM bracket, and everything kept running - no freezes lockups.

Sadly, given my experience, this issue will surely come back. I'm in the process of getting a new laptop, so that I won't run into this issue incessantly in the future. Nonetheless, it is frustrating that having had this laptop in the Genius bar multiple times for this issue, there has not been a fix.

All that to say, if you're trying to salvage your MBP, keep tweaking that RAM bracket. No need to replace RAM, logic board, etc. Just keep tweaking - that's all I can suggest. I do think as was said above, that this is related to the MBP getting really warm and things shifting, but not sure how to fix it permanently.

I have exactly the same problem. Second RAM slot not recognised after installation of Mountain Lion. Refuses to wake up after closing the lid. Only way to get mac working again is long presses of the power button to reboot. This problem has continued for about 6 months. The geniuses at Apple are not very clever because they were completely unable to assist. I replaced all the RAM but to no avail. I will be trying the screw loosening thing. Questioning whether Apple products really are worth all the money now.

I'm having this same problem ... except for now my computer will only recognize 1 memory stick (2gb RAM).

I have a macbook pro mid-2009, 2.26ghz

I have 2 x 2gb of Ram; one in each slot.

Slot Bank 0 recognizes the 2GB of RAM; Bank 1 says "empty" but there is actually a 2GB RAM stick there.

I opened up the back of the computer and switched the RAM sticks to make sure that each work; same result. It appears then that Slot Bank 1 has gone bad.

Now I'm thinking I need to replace the logic board? But petepete0pete said that the Genius bar replaced his logic board twice and the problem persists? What is the fix for this? Can I replace just the RAM slot bank? Do I need to replace the logic board memory?

Thanks

I have MBP 13" mid 2010, i think i have been running it on one ram for the past 2 or 3 years.
I can connect to all the stories about sleep issues because when the MBP was around one years old they started, i used all the tricks clearing smc, clean OS X etc.. finally the sleep issues stopped i guess it was then memory bank 1 became "empty".
Found out about this problem when i was going to upgrade my Ram from 2 GB (thought there were two 1 GB Ram modules but they were two 2 GB modules in the computer) to two 4 GB modules.

I was able to fix this by stuffing folded shopping receipts on and around the two modules(do on your own risk) but sometimes the computer wont wake up from sleep because connection is lost.

What I find weird about this is that if I remove one module the computer wont start.. so there must be some connectivity?