Only 32-bit VMs possible

[Detlef]

After installing the latest virtualbox-version, I can no longer create 64-bit VMs, but only 32-bit VMs. Also I can only use 1 CPU.
Anybody got an idea why?

[derikkk]

Hello to all! Can I join to topicstarter's question?

I start using latest VirtualBox (4.3.20 r96997) and now I can create only 32-bit VMs. 64-bit VMs not present in list.

This problem repeats on 3 different systems:
1) Core2 Duo E8400 + MB ASRock P43DE3 + 8GB RAM + Windows 8.1 x64
2) Core i7-3770 + MB ASRock Z77 Pro4 + 8GB RAM + Windows 8.1 x64
3) 2*Xeon E5-2420 + MB Supermicro X9DBL-iF + 32GB RAM + Windows Server 2008 R2 Enterprise

On ALL systems "Intel Virtualization Technology" is ENABLED in BIOS and 64-bit operating systems installed.

I don't know what should I do in further?

[frank]

A VBox.log file of a VM session of one of your guests should contain information explaining your problem.

[mpack]

FAQ: I have a 64bit host, but can't install 64bit guests.

[derikkk]

A VBox.log file of a VM session of one of your guests should contain information explaining your problem.

Maybe a VBox.log file of a VM session of one of my 64-bit guest can contain more information. But I haven't 64-bit guests because I can't create any 64-bit guest.

When I want to create VM I open corresponded dialog. For example in "Name" field I type abstractive name of future guest VM, in "Type" list I select "Microsoft Windows" or "Linux" and in result "Version" list contain versions only with "(32 bit)" suffixes. In example "Windows 2008 (32 bit)", "Oracle (32 bit)".

FAQ: I have a 64bit host, but can't install 64bit guests.

Really, on my host with Windows 2008 R2 Hyper-V role is installed. OK, thanks a lot!

On one of my hosts with Win 8.1 (Professional Edition) I disable Hyper-V component in Windows Components and this problem has been solved. But on second of my hosts with Win 8.1 Pro too Hyper-V initially wasn't enabled. But problem is present. What other apps may use/occupy VT-x? Mostly used are Beholder TV-tuner app and different internet browsers.

[mpack]

All of the possibilities are listed in the FAQ, including common culprits for "who's hogging VT-x?". Be sure to consider each item in the checklist, prove each requirement satisfied before moving to the next.