If you are getting “Zero Downtime Mode is Not Running” message while middle of your operation then you can check the following solution…

I have got this message screen while “EHP7 Stack 10″ upgrade operation was working…

Then we should check the following steps ;

1. Log on to the shadow system
2. call transaction CRR_CONTROL
3. check the replication state

Shadow system’s CRR_CONTROL output ;

We have to “Start Transfer” before continue to our process.

For this ;

Control –> Start Transfer

Now we should see the status GREEN like below

Now we can try again with the option “Check Status Again”

And i hope that you will get the following “completed” screen for the related phase.