The other day I needed to add a large amount of objects (860) to an availability report. After the report ran I noticed that only 500 objects were present in the report view, as it turns out this is by design.

In your registry you need to browse to the following key:

Location: HKEY_CURRENT_USER\Software\Microsoft\Microsoft Operations Manager\3.0\Console

Create a new DWORD value key that is named MaximumSearchItemLimit, and then assign it a decimal value to reflect the number of objects that you want to display. For example, use a value of 1000 if you want to limit the maximum number of objects to 1000 instead of the default of 500.

Name: MaximumSearchItemLimit
Type: REG_DWORD
Value: 0 to 65535

Close and re-open your console.

You will now be able to search the number of objects that you set the value to.

Note: This needs to be applied on each machine running a console that you want to remove the restriction from.