The DEP Data Execution Prevention is a security feature that has been available since Windows XP SP2. You will also find this feature in Windows 7, 8 or 8.1.
It’s trying to prevent that certain applications and services can execute code from a non-executable memory region. It’s a useful feature that can help to prevent a buffer overflow and it even helps to fix problems for some games like “Age of Mythology, but it can also cause a lot of problems.
What is the “Data Execution Prevention”, short DEP?
Several users reported that they are no longer able to boot their computers after disabling DEP (Data Execution Prevention). Only follow this guide if you know what you are doing. At your own risk! You may lose all data permanently. The solution is to boot into safe mode (F8) and enable DEP again, but it’s not guaranteed to work.
I am posting this solution how to disable and enable the Data Execution Prevention on request of a reader who had serious problems with this feature:
Question asked by Raaghav K.
I was using win7 for little bit time
it was not supporting softwares which were supported by XP
I guessed it to be the Data Execution Prevention in the 7.
While there might be other causes why your software is not running, I’ll try to explain you how you can turn off the DEP.
By the way, I sent a mail to all subscribers that all of your questions are more than welcome. I will try to answer them all, but give me some time so I can answer them properly. You can always post a question on our forums or send me a mail!
Does your CPU support Data Execution Prevention?
- Open the Explorer (Windows key + E) and right-click on “Computer”. Select “Properties” from the context menu.
- On the left click on “Advanced System settings”, click on the “Settings” button of the field “Performance”:
Go to the tab “Data Execution Prevention”:
On the bottom you can see if your CPU supports DEP.
If you want to find out if your CPU also supports “Hardware Virtualization”, then I recommend to download the tool:
“SecurAble” (which has been downloaded about 700,000 times!
As you can see above my CPU, an Athlon 64 X2 5000+ supports Hardware D.E.P. and Hardware Virtualization.
You can download SecurAble here.
Although this is about DEP, I want to quickly tell you what Hardware Virtualization is.
Quick Sidenote about Hardware Virtualization
Hardware Virtualization or better “Hardware Assisted Virtualization” is basically the built-in hardware support of CPU’s that is needed to run virtual machines more efficiently:
What the industry has seen lacking was support for virtualization at the hardware level to boost the performance of the VMM. This is because the x86 processor architecture did not previously meet virtualization standards, making virtualization on the x86 platforms difficult. Starting in 2005 both AMD and Intel made changes to their x86 architectures and added virtualization-friendly extensions.
On a second sidenote, Sony Laptops that run Windows 7 will have HardWare Virtualization disabled by default and therefore no Windows XP mode. However, you can re-enable it via BIOS settings.
How to disable Data Execution Prevention
Alright, as you can see above, you can’t simply disable the feature with a few clicks (that would be too easy, ha!)
1. Step Open the command line: “Start” -> enter “cmd.exe” into search field and hit enter.
2. Step Simply run the following command to disable it:
bcdedit.exe /set {current} nx AlwaysOff
3. Step You can enable it again with:
bcdedit.exe /set {current} nx AlwaysOn
If you run this command and you are not able to start Windows, then run Windows in safemode and enable it again, using the command above. Start Windows in safemode by pressing F8 during bootup.