Ever since I had problems with vDP showing up in vSphere Web Client, there has been problems with the Integrity Check.
First, my integrity check failed every time it tried to run. When I would force run it from the GUI, it would fail. I found this great article on VMware KB that was about force running it through command line and it worked really well.
The second issue that I came across is that it still failed after I forced it through the command line. Since running it through the command line isn’t the good for long term, I had to dig into it further. The first thing I tried was upgrading my RAM from 4GB to 6GB. Seems simple, but it worked.
If you don’t know how to force run an integrity check from the GUI, connect to your vDP client through the vSphere Web Client, click on the “Configuration” tab, then select the gear looking icon and from the drop down select “Run integrity check”.
If you’re having trouble with integrity checks, I would force run it, then up my RAM. I’m not sure why adding more RAM worked for me since I’ve been running it for months without any problems, but that is what seems to have fixed it for now.
Virtualizing IT 
Thanks for the post as I’m running into this issue as well. I suspect it might have something to do with retention as I set mine to 90 days about a month ago. So maybe the higher the retention the more system memory required, but that’s just a guess.
Joe,
Are you using the free or advanced version? I’m currently using the free version and have tons of problems with it.
Thanks for the tutorial. In the VMWare Data Protection documentation has writen the integrity check ran in the maintenance mode, but do you know what is the specific time which integrity check runs? I want to lock the integrity check execution only on non-work hours because the task is much I/O intensitive so it can cause me performance downgrade…