Hi,
As pe your input and suggestion I followed your procedure but before that i did mass erase and then recompiled all the project one by one. After mass erase I initiated for the first time to debug then the IDE stuck at one point mentioned below

It stuck for long time so to come out of this loop I did Clean up to kill the active debug components.
Again initiated to debug the M4 Project. But again got stuck in the below mentioned point. so to come out of this loop I did Clean up to kill the active debug components.
Deleted the launch and .jtag file of M4 project and again initiated to debug the M4 Project. Again got stuck in the below mentioned point. so to come out of this loop I did Clean up to kill the active debug components.
Then I Reset the controller and then click on debug icon and it got programmed. The I tried to programme M0Sub project and I got this error.

I don’t understand why it gives this error shown below.
“ 15: Target error from Set break/watch
Unable to set an execution break - no resource available.
Debugging context: M0Sub_FPR LinkServer Debug”
Then I clicked to cancel to terminate the session. Then it terminates both M4 and M0Sub session. Again initiated to debug the M4 Project and I got below error,

Again I need to do Mass erase using GUI flash tool to reinitiate debugging, Then the M4 Project was programmed.

Then initiated to launch debug for M0Sub Project. And it got programmed

Then I initiated to launch debug for M0App Project. Then I got the same error again,

Now this time it is for M0App project and every time when this error comes and I click on OK ot goes to ResetISR(void) function of M0App Project.

Again I need to do Mass erase using GUI flash tool to reinitiate debugging for all the Projects.
I am able to programme M4 Project but while launching M0Sub project it again gives error

Now this is a random behaviour since sometimes it comes for M0App and sometimes it comes for M0Sub but for M4 Project it gets launched successfully every time. when I click on OK to goes to ResetISR(void) function of M0Sub / M0AppProject.
This all the procedure I tried with the older version of the MCUXpresso V10.1 in my laptop, there also for the first time when i did mass erase and then inititated the programming it programmed all the core / Project but when I do relaunching after termination it shows "Target error from write flash EF(50)"

Then i have to do Mass erase using Regaining debug access to target MCU and tried to relaunch the project , than it is observed that M4 Core is programmed successfully all the time but when it come to M0App and M0Sub project it is the random behaviour and it goes to the reset ISR function as already mentioned above.
I am not able to get the reason for the error
"15: Target error from Set break/watch
Unable to set an execution break - no resource available.
Debugging context: M0Sub_FPR LinkServer Debug”
Whats is the cause for this error. If no resource available then why for the first time it got programmed successfully? . This happens when we terminate the debugger and agian relaunch the debug session.
After that i am not able to launch the Project with all core.
I am unable to get the sequence as to when and what to do to relaunch the project since I am modifying the code and then testing the project so relaunching shall happen many times.
I suggest you perform following steps.
1. Mass erase using GUI flash tool
2. Launch the project (M4. M0Sub and M0App)
3. Run all the projects
4. Terminate all the projects .
5. Again relaunch the project as per the required sequence and then check the behaviour.
All this procecure when I performed with LPCXpresso IDE, I did not find any error and it is working properly.
Please check the same and let me know ASAP. Mean while i will check other peripheral of my development board using LPCXpresso IDE.
Thanks
Gaurav More