Tyrbiter yah right haha! I can only tell you what worked for me and that is - did a complete factory reset to the 578 - downgraded to v1.15 then loaded the cps using csv files for only items needed - channels, talk groups, zones etc. completely rebuilt codeplug from scratch - which totally resolved the issue. I do not have the annoying noise any longer so in my case it is not an openspot 4 pro issue! 73