The most common issue that causes the DVR+(CM-7500) not to record, have choppy video and behave strangely is usually a defective or unsupported hard drive.
Channel Master has thoroughly tested a few specific Seagate hard drives that are listed on the DVR+(CM-7500) page on our website. If you are not using one of these drives it is highly likely the DVR+(CM-7500) may not be compatible with your hard drive. We have specifically seen issues with 2TB Seagate hard drives and homemade internal PC drives in enclosures. If either of these are your case, we recommend trying a different hard drive preferably one that is recommended by Channel Master.
Many of the shelf hard drives will work fine with the DVR+(CM-7500) but it's not practical for Channel Master to test every single drive on the market for Ideal performance so we strongly suggest the hard drives that we recommend but you may try any other drive at your own risk, the only downside is if it does not work you may need to try another one.