obsolete software key

When I ran "scan for issues" I get:

1) an "obsolete software key" entry.

2) Under the data fielf it lists: "PSH_TBX_USED_FLAG"

3) Under registry key it lists: "HKLM\SOFTWARE\PSH_TBX_USED_FLAG"

Once I fix the issue, using CCleaner, it removes this entry from the registry, however, when I reboot this system and scan for issues again, this same entry shows up again.

Does anyone have any thoughts as to what this entry might be?