If I encounter a situation where I suspect my machine's RAM might be going bad, I might need to launch memtest86+ to check it. How can I do this using Ubuntu? Are there different methods for launching it whether Ubuntu is already installed?

* (This is intended to be a canonical question easy for new users to follow.)

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    I would suggest running it overnight if possible. I had long running problems caused by faulty RAM and it took 11-12 hours of testing before the errors appeared. – JohnW Mar 3 '15 at 19:38
up vote 53 down vote accepted

memtest86+ comes default with Ubuntu and you can try it from live CD or from any installation of Ubuntu. Here are the steps:

  1. While booting press (better hold down) the Shift key to bring the grub menu that looks like the following image:

entering grub

As you can see there are some options to choose from (this will vary from installation to insatllation), the one to look for is the third option in this screenshot i.e. Memory test (memtest86+), which will be there in the grub menu along with other options.

  1. From the grub menu go to the appropriate option to select i.e. Memory test (memtest86+) and press Enter.

select memtest

  1. Now you will see a blue screen indicating that the memtest is running:

memtest running

  1. Now you can press c for more configuration options:

selecting conf options

  1. To exit from the memtest86+ session you can press Esc any time. There is no certain rule that how many passes you would run but the more the better.

Here is an image (taken from here) showing that errors were encountered i.e. the test is failing in some memory locations (pointed out in the red portion) indicating the locations might have problems. If your memory does not have any problem then you won't get any red portion.

error message

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    I know this is an old thread but just in case someone is still paying attention: any idea how to get the memtest option in the grub menu for 64 bit / EFI systems? – ElRudi Aug 21 '16 at 19:25
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    @ElRudi the latest version is available here and supports UEFI memtest86.com/download.htm How to add it to the menu is here askubuntu.com/questions/126160/… – Elder Geek Aug 23 '16 at 23:11
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    I have memtest86+ (it appears in the Ubuntu Software centre) but when I follow these instructions it doesn't appear in the GRUB screen as shown in 1 above. Any suggestions as to how to get this working? – user1945827 Dec 11 '16 at 12:48
  • @user1945827 See the question that Elder Geek linked to in the comment above yours; that most likely is what you're looking for. If that still does not work for you or is not quite what you need, then consider asking a new question. – Christopher Kyle Horton Apr 26 '17 at 4:06
  • Thanks @ChristopherKyleHorton I'm just working through it but I need a bit of help from the person who gave one of the answers I'm following. When I type XXX@ubuntu:~$ cat /boot/grub/grub.cfg | grep memtest ### BEGIN /etc/grub.d/20_memtest86+ ### ### END /etc/grub.d/20_memtest86+ ### I get the two lines generated ... but I think I should have something in between them. I've asked for clarification; if nothing is forthcoming I'll take up your suggestion and start a new question. – user1945827 Apr 26 '17 at 21:34

To perform a memory test on Ubuntu Live CD and Installed system.

Turn On or Restart the system

Hold down Shift to bring up the GRUB menu.

Use the arrow keys to move to the entry labeled Ubuntu, memtest86+

Press Enter. The test will run automatically, and continue until you end it by pressing the Escape key

Allow the test to run for at least one full pass.

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