I have no idea why, but no matter what version of Horizon, and Windows 10 (including LTSC), Horizon cannot create a linked-clone pool of non-persistent desktops using sysprep or quickprep. Windows 7 worked perfectly, never had any issues.
Environment:
ESXI 6.7u2b
vCenter 6.7u2b
HP SimpliVity DL380 Gen9 Nodes (all flash storage, file stores are NFS format, supports VAAI)
Horizon 7.10 (however, this issue has persisted for many 7.x versions)
I use Citrix App Layering typically to produce a composited gold image, but even using an image that has been strictly built in ESXI, the problem happens. Sysprep always fails with an error about being unable to remove user-provisioned apps with no specific packages specified in the message (AppX, it appears.) I've tested with all AppX packages removed for all users, no AppX packages removed at all, and even with 2016 LTSC that doesn't even have AppX packages, and it's always the same error. This has persisted across several Horizon 7.x versions, ESXI 6.5, 6.7, and Windows 10 versions. I've deleted/recreated/altered pretty much every setting in the vCenter response profile, and it's always the same. The exact error message is always the same, and if you attempt to find it online, it's not referenced anywhere.
Quickprep will compose OK, but when it attempts a refresh, it throws out an error about the checkpoint disk already exists (it should, it's a linked-clone) and goes into error status. Sometimes you can reboot it and it works, other times it has to be completely recomposed. Functionally useless.
Windows 7 never exhibited these problems, and Server 2016 doesn't either, under the same (approximate) configurations. It does create a disk digest for the replica (in sysprep mode) and a digest for every VM in quickprep mode, which appears to work OK, but quickprep doesn't seem to like having a delta disk. The datastore for all the Horizon-created VMs is the same, NFSv3 (I did test against a VMFS store with the same results) with VAAI snapshots are enabled.