Hyper-V VHD expanding everyday. How to reduce the VHD Size.

In normal usage, and over time, some VM's grow when dynamic disks are used. This is a good thing if you need them to grow, but, in your case, since you don't have much room for them to grow, I would say you have two choices.

1. Establish a schedule for compacting the disks. This should be done often enough to avoid the disk attempting to expand more than it has capacity to do so.
     - If you have 10GB of room and you grow 1 GB per day, then you must compact at least every 9 days.

2. Rebuild the VM's as "fixed disks" to keep them from growing dynamically. The downside is - you may run out of disk space for paging, normal operations, etc. but at least your VM's will NOT expand and fill up the actual partition they are on.

Let me know if this is helpful, or, if I misunderstood your situation.

I am wondering why only these 2 VMs expanding like this.
I think I gave 127GB HDD space for these 2VMs.  Could be bcoz of that?
Rest all 3 I gave 50GB space in the VM

And recently installed windows7SP1 automatically by the windows update.
This could be the reason?

As far as I see the issue has been cause by the fact that the initial 250GB space has been split in 5 partitions. This was not a recommended configuration and it basically removes one the main advantages of virtual machines, like sharing disk space.

As a long-term solution I would recommend reverting back to a single space for all VHD files. There are two ways to do it, depending on where the config files are located. If they are located on the same 50GB volumes then the only available solution will be to export all virtual machines, delete them from Hyper-V manager, remove all 50GB partitions and create a single one of 250GB, then import the virtual machines back. If the config files reside on different volume, then you don’t need to export/import the full VM – only copy the VHD files out and then back to the big volume and reattach them to the VMs. Note, that you must not have snapshots if the second method is used.

@Svet Paperov
I know it is not recommended but I am having another RAID array with is less than 250GB
I am mirroring the partition to the other partition in the second RAID using windows mirroring.

What is different about these two VMs? What is it that is grabbing the extra space?

It's recently updated by SP1 and few other updates. It has HDDsize 127gb

I noticed one thing today. The other VMs also started the same issue.
This is bcoz of windows updates and SP1 installation.

How to reduce the size ?

@Moderator
Appreciate if you can keep it open for couple of days more as the proposed solutions was not successful yet.
Or if you want me to close and reopen please let me know

Thanks to all experts