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Check memory modules with Memtest86+

By , logo. Last updated: 2017-10-06

How to use Memtest86+ for testing if your computer's RAM (random access memory) is working correctly

You need a blank CD-R or CD-RW and a CD-writer, or a blank USB or floppy disk to follow instructions in this article.

Please note that the USB method applies to USB thumb drives only, external hard disks are not supported.

If you have no CD-writer or USB boot support, but you do have a floppy disk drive, you can create a bootable floppy disk for memory testing.

Because the selected media will be formatted in the preparing process, make sure your CD-RW, USB flash disk or floppy does not contain anything important.

Why should your computer's memory be tested?

If you have your Windows locking up (hanging) or doing random reboots for no apparent reason, then the problem often lies in defective memory. If you have overclocked your computer's processor or set the memory timing manually, try reverting back to defaults - this might help more than you can imagine.

Do not ignore faulty memory modules, for this can easily lead to data loss - hard disk or SSD contents messed up or even deleted.

Downloading Memtest86+

Open Memtest86+ home page.
To get the bootable CD image, click Download - Pre-Compiled Bootable ISO (.zip). Be sure to click on the link with "(.zip)" at the end, the other one cannot be opened by Windows Compressed Folders program.
Memtest86+ download page. Click 'Download - Pre-Compiled Bootable ISO (.zip)' to get the bootable CD image.

To get the bootable USB thumb drive image, click Download - Auto-installer for USB key (Win 9x/2k/xp/7).
Memtest86+ download page. Click 'Download - Auto-installer for USB key' to get the bootable USB disk image.

To get the bootable floppy image, click Download - Pre-Compiled package for Floppy (DOS - Win).
Memtest86+ download page. Click 'Download - Pre-compiled package for Floppy' to get the bootable USB disk image.

In File Download dialog, click Open.
Internet Explorer 8 File Download, click Open Internet Explorer 9 File Download, click Open

Extracting the downloaded file contents

After download is complete, Windows will open it with Compressed Folders program unless you have some other file compression program (such as 7-zip, WinZip, WinRAR) installed.

In Windows Vista and 7, click the Extract all files button on toolbar.
In Windows 8/8.1 and 10, click Extract all on Ribbon. If Ribbon is not visible, use keyboard shortcut Ctrl+F1 to reveal it.
In Windows XP, the Extract all files command is in Common Tasks Pane on the left. If you have disabled Common Tasks, use keyboard shortcut Ctrl+A to select all files and then select Extract command from File menu.
Windows 7, Compressed Folder. Click 'Extract all files'. Windows 8 folders. To extract all items from the selected .zip file, click 'Extract all' in Extract tab of Ribbon. Windows XP, Compressed Folder. Click 'Extract all files'.

Windows Vista, 7, 8, 8.1 and 10 users should click Extract and all files will be extracted to a new sub-folder. The new folder will open automatically after this.
Windows 7, Extract Compressed (Zipped) Folders. Click Extract.

In Windows XP, extracting the compressed files includes many more steps.
First, Compressed (zipped) Folders Extraction Wizard appears with Welcome page. Click Next.
Windows XP, Compressed (zipped) Folders Extraction Wizard, Welcome. Click Next.

In the Select a Destination page, click Browse to select a better destination folder. By default, the not-so-wise wizard wants to extract all files into Temporary Internet Files folder.
Windows XP, Compressed (zipped) Folders Extraction Wizard, Select a Destination. Click Browse.

Select a destination dialog opens. Click OK to extract the files into a new sub-folder in My Documents folder.
Windows XP, Compressed (zipped) Folders Extraction Wizard, Select a Destination dialog. Click OK.

Back in the previous page, click Next.
Windows XP, Compressed (zipped) Folders Extraction Wizard, Select a Destination. After selecting My Documents as destination folder, click Next.

Finally, click Finish. The new folder will open automatically after this.
Windows XP, Compressed (zipped) Folders Extraction Wizard, Extraction Complete. Click Finish.

Preparing the bootable media

For the downloaded CD image, Windows XP, Vista and 7 users should double-click the mt<version number>.iso file to open it with default disc burning program.
Windows 8/8.1 and 10 users should right-click the file and select Burn disc image from the menu - by default, Windows 8/8.1/10 mount disc images as new drives.
Windows 8, Windows Explorer, ISO files. To burn the selected ISO image to CD or DVD, right-click it and select 'Burn disc image'.

For the downloaded USB image, insert your USB thumb drive and double-click the Memtest86+ USB Installer.exe executable file to start the program.
For downloaded floppy image, double-click install.bat in folder named floppy.

Creating a bootable Memtest86+ USB drive

After double-clicking the executable file, Windows checks for digital signature in the file. Because the file is not signed, Windows XP will pop up an Open File - Security warning dialog. Click Run. Windows Vista, 7, 8/8.1 and 10 users will see the most beloved User Account Control warning instead. Click Continue or Yes.
Windows XP, Open File - Security Warning for Memtest86+ USB Installer. Click Run. Windows 7, User Account Control Warning for Memtest86+ USB Installer. Click Yes.

Memtest86+ USB Installer Setup opens with License Agreement. Click I Agree.
Memtest86+ USB Installer Setup, License Agreement. Click 'I Agree'.

In the Choose USB drive location page, select your USB Flash Drive letter and tick the (Recommended) Check this box if you want to format drive box.
Only USB thumb drive letters are displayed here, no external or internal hard disks can be selected for security reasons.
Memtest86+ USB Installer Setup, Choose USB drive location. Select your flash disk drive letter. Enable the '(Recommended) Check this box if you want to format Drive' option.

Make really-really sure you have selected the correct drive letter and that you do not have anything important on the USB thumb drive. Then click Create.
Memtest86+ USB Installer Setup, Choose USB drive location. Click Create.

The process will take a minute or two, just stand by. Click Next after the Memtest86+ bootable USB drive creation is complete.
Memtest86+ USB Installer Setup, Installation Complete. Click Next.

Finally, click Finish.
Memtest86+ USB Installer Setup, Installer has completed the installation. Click Finish.

Creating a bootable Memtest86+ CD

First, insert a blank CD or CD-RW. Windows XP and Vista users can use a free CD/DVD writing program, such as CDBurnerXP.
Windows 7 and later include the Disc Image Burner program that you can use for burning ISO disc images to CD-s and DVD-s. Click to check the Verify disc after burning box.
Windows 7 Disc Image Burner. Check the 'Verify disc after burning' box. Insert a blank CD or CD-RW and click 'Burn'.

If you inserted a CD-RW with some files already written on it, Windows Disc Image Burner will ask whether you want to erase the whole disc contents or not. Make sure you do not have anything important on the disc and click Yes.
Windows 7 Disc Image Burner, Erase Disc. If the CD-RW you inserted has some contents, it needs to be erased first. Click 'Yes' to blank the disc and write the image on it.

The disc burning will start. As the image file is not big (around 2 megabytes), it will take only some minutes until the burning is complete. Disc Image Burner will notify you with "The disc image has been successfully burned to disc" message in Status box. The disc will be ejected after this. Click Close.
Windows 7 Disc Image Burner, the disc image has been successfully burned to disc. Click Close.

Creating a bootable Memtest86+ floppy drive

A black command prompt window will open with Memtest86+ description. There might be some line about invalid CON code pages or an absolutely strange line with messy characters, just ignore that.
After a few seconds, a line Enter target diskette drive: appears.
Press A on your keyboard (if your floppy drive letter is B, then press B key). Then press Enter key.
Memtest86+ floppy installation, Enter target diskette drive. Press the key with the letter of your floppy disk drive and then press Enter.

If you still haven't inserted your blank formatted floppy disk, insert it now. Then press Enter as told on the screen:
Memtest86+ floppy installation, insert a blank diskette and press Enter

After a few seconds Memtest86+ installation is complete. Press any key (Enter, for example) to close the command prompt window.
Memtest86+ floppy installation complete, press Enter to close command prompt

Now close all open programs, leave the CD, USB drive or floppy disk inserted and restart your computer.
If you have correctly configured your computer BIOS/UEFI to boot from the CD, USB or floppy disk, Memtest86+ will start automatically after the restart.
If not, Windows will probably start again.

Memtest86+ at work

Memtest86+ offers Fail-Safe Mode for a few seconds before starting the memory test. If your PC has stopped responding or rebooted by itself during previous tests, press F1 key.
Normally, you do not need the Fail-Safe Mode.
Memtest86 startup. If your computer reboots or stops responding during the test, press F1 key to use Fail-Safe Mode.

Let Memtest86+ run for 15-20 minutes before checking any results. Although Memtest86+ will easily run for hours, the first 15-20 minutes will always confirm the state of your memory modules.

If a memory module is not working correctly, Memtest86+ might stop responding or reboot computer. Check that WallTime value is increasing every second and use Fail-Safe Mode the next time.

If after 15-20 minutes values in last two columns, Errors and ECC Errs are 0 or empty, the memory in your computer is fine. ECC Errs will be displayed only if your computer and memory module(s) support ECC (Error-Correcting Code).
If an error count is over 0, you must replace the defective memory module(s). As said before, defective memory will lead to unexpected errors, random reboots and data loss.

Here is a computer with good memory modules.
Memtest86+ in action - 0 Errors, blank ECC Errs. Memory is fine!

To exit Memtest86+, press Esc key on your keyboard. Your computer will reboot. Remove the CD, USB or floppy disk and let Windows start normally.

If your device's memory module(s) is/are defective

Because there are very many different memory module types (such as DDR, DDR2, DDR3, DDR4 etc) and they also have different working speeds, I recommend using free HWInfo or Speccy to determine which memory module(s) your computer needs and whether there are available memory slots. The point is that you cannot put just any memory module in your computer. A possible solution is in the manuals that came with your computer - supported memory types and speeds are listed there.

If you have overclocked your computer, try changing settings back to defaults first. Memory modules might not be able to run at higher speeds or voltages.
Then run Memtest86+ again.

If your computer is still under warranty, check the manuals that came with your computer to find out where to call or where to take your computer.

If you do not know much about computers and parts they consist of, I strongly recommend having memory modules replaced by a specialist. Otherwise you might end up with broken memory modules, electronic parts ruined by static electricity, unintentionally unplugged cables or some other malfunction.


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