Shared VHDX sector size mistmach
Right now if you create a shared VHDX and there's a mismatch between the physical/logical sector size between the physical volume and the VHDX, Hyper-V lets you mount the VHDX but the initialization of the disk fails in the guest with a generic IO error. It would be nice to have some sort of validation done by Hyper-V or that it would support the various sector size for shared VHDX no matter what.
See the following article:
One of our goal was to convert an existing file server VM into a guest cluster but because of this we either need to migrate all the data over to a VHDX with the proper sector size or we need to create a new Storage Spaces virtual disk to accommodate the VHDX sector size. Kind of a pain!
I believe this hotfix covers the issue you are describing https://support.microsoft.com/en-us/kb/3025091