IE tabs are not running in 64 bit mode even after enabling Enhanced protected mode

Question

I would like to run my desktop IE tabs in 64 bit mode. As described by Microsoft I have enabled IE enhanced protected mode using IE Tools->Advanced options. I have also enabled "Enabled 64 bit processes for enhanced protected mode". Nevertheless I am unable to see IE tabs running in 64 bit mode.

Note: I am using IE11 in Windows 8.1 64 bit machine.

Answer 1

The solution is to add a registry key in: HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\TabProcGrowth with value 0.

Works for Windows7 and IE11 (see here: https://support.microsoft.com/en-us/kb/2716529)

You could use a reg file instead of manually setting the registry key. Just save the below text in a file named as key.reg and double-click to execute it:

Windows Registry Editor Version 5.00    
[HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main]
"TabProcGrowth"=dword:00000000

Answer 2

Another reason it is that the Isolation64Bit reg value might be set.

Check in IE Tools -> Options -> Advanced and untick Enable 64-bit Processes for Enhanced Protected Mode if it's ticked.

Alternatively check the following reg keys:

HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Internet Explorer\Main\Isolation64Bit
HKEY_LOCAL_MACHINE\Software\Microsoft\Internet Explorer\Main\Isolation64Bit
HKEY_CURRENT_USER\Software\Policies\Microsoft\Internet Explorer\Main\Isolation64Bit
HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\Isolation64Bit

and if any of them exist (and are set to 1) then set it to 0 or delete it.