Hi Faris Fawzi,
Thanks for your post.
It is recommended to remove the checkpoints of your VMs in the Hyper-V Manager or using the powershell command Remove-VMSnapshot. Deleting the differencing virtual disk files directly will cause the virtual disk chain broken.
If the avhdx files cannot be merged automatically, you have to try merging them manually. Please refer to the following links.
https://www.nakivo.com/blog/merge-hyper-v-snapshots-step-step-guide/
Best Regards,
Ian Xue
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