Ok - nothing sensible received from IOBit support.
Research shows IOBit is a Chinese operation accused by MalwareBytes of having unlawfully used or reverse engineered their product.
I saved a rather important document today only to discover that it too had vanished without a trace.
Conclusion.
IOBit is to be avoided at all costs.
Advanced system care now deleted.
IOBit 360 now deleted.
CCleaner run.
Malwarebytes full scan clean result.
Unable to save any files and retrieve them.
What time is the next bus to square one ?
SF
