Hello !
I have windows 8.1 on a standard MBR partition.
Is possible to convert to GPT without loosing the installations I made ?
( Of course the Bios support UEFI ).
Thank you !

You may kindly go through the following article:

How to Convert MBR to GPT Disk in Windows 8 / 7

Thank you !

But the comments in this link says that are problems with these methods.

Actually , my HDD configurations where I have installed windows 8.1 is this :

Partition..............Type.......................Size......................Offset
Partition1...............Primary........................268GB.........................31 KB
Partition2...............Extended.....................197GB.........................268GB
Partition3.................Logical........................197GB........................268GB

so how should I made this convertion ?

Thank you !

Hi,

We cannot ensure the third-party tool safety.

For built-in tool, either using Windows interface or command line, back up or move the data on the basic master boot record (MBR) disk you want to convert into a GUID partition table (GPT) disk. It cannot remain your data.

For more information, please read this article:

Change a Master Boot Record Disk into a GUID Partition Table Disk

https://technet.microsoft.com/en-us/library/cc725671.aspx

What is the reason you want to convert your disk type to GPT?

Disk Management in Windwo 8.1 only allows you to convert MBR to GPT on an empty hard disk, if there are data on hard drive, you must delete all of them in advance. to avoid deleting data, you can use third party aoftware such as AOMEI Partition Assistant

Yes  , I have tried several third party software , but after the conversion , the data is saved but the windows 8.1 is not bootable anymore.

Only way to do it: Change a Master Boot Record Disk into a GUID Partition Table Disk

You mean  : Only way to do it ..... with loosing data ?

I have not asked about this. I wrote that using 3d party software I can make the conversion without loosing data  , but windows will not be bootable anymore. This is what I want to fix it.

Hi,

We don't know third-party tool how to operate. It has damaged the system file lead to Windows cannot boot. You May consider to do a lean installation or contact that tool's support for help.

After converting MBR partiotion to GPT you must update Windows BCD configuration. Check this article.  The article applies to Windows 7, but apparently should work for Windows 8 too.

Hello.

There would be a number of issues with booting Windows, listing a few, probably more, so it's not surprising Windows is not booting.

The boot and system volumes may be different after the conversion. ( the boot files need to be on the EFI system volume on a GPT disk)

the boot files including the BCD but not limited to the BCD are different.

The volume GUIDs may have changed after the drive was converted so the drive lettering may be different after the conversion in Windows.

You should perform a backup of your data and then you can restore it.