I thought it would be worth popping this into a blog post as I spent many hours recently troubleshooting problems with the Windows 10 Start Menu and Search bar in a Citrix PVS environment.
In some instances the Start Menu was slow to load up or other instances wouldn't load at all, occasionally prompting for the explorer.exe process to be killed.
The root cause behind this problem turned out to be VMWare Tools.
The version that fixed it for me was release 9.4.15-2827462 which is the baseline release for ESXi 5.5 Update 3.
The version 10.x versions I tested 10.0.0.3000743 & 10.0.9-3917699 just didn't work, 10.0.9-3917699 being the latest release.
You might find other version 10.x installs are just fine but this article just highlights the problem.
Note you can download the VMWare Tool packages from here https://packages.vmware.com/tools/esx/index.html