Since of late I am having major picture quality issues when using my DVR and old iMac. It worked well for the longest time and suddenly I have picture quality issues. See attached and pls help 
This type of corruption is common when signal is dropping at the antenna or packets are dropping on the network.
Check the signal quality and strength on my.hdhomerun.com while a recording is happening.
Is the DVR running on a wired machine or Wi-Fi?
Thanks for the information. It’s running on wireless AC. Connected to a the wireless google bridge. I believe what could be causing an issue is the zwave plug that I have setup close to the wireless endpoint & iMac . I shall remove it and check if the behavior continues.
We don't recommend making recordings over Wi-Fi.