The Zener diode protection from short circuit with help of watch dog resistor

Reduce min and max output voltage of opamp to -8.and 8 Volt in opamp settings, and simulation will start. I can't conclusively explain this at.this point, but noticed earlier that this setting affects ability of EC to start simulation.

Feedback not correct. Change top 1k resistor to 4.7k.

That will allow it to run without error but you may want to make other adjustments. For example, zener current should be close to 13.6mA so increase zener resistor to 1.2k.

Thank u bro

If you make the changes I suggest you don’t need to alter the power rails of the op amp.

Other adjustments are required.

So guys, from what information you know what the output voltage is suppose to be??? 8,9,10,12 or 15V??? I do not see any information. Only an output 1:1 voltage divider which gives half the output compared with 4V reference needs an output voltage of 8V. After one Ube will be dropped by the BJT, that mean the opamp need a voltage 8V+0.7V =8.7V at least to give 8V at the output. To limit its rail to 8V just hides the problem and wont work for a regulator. Its a know EC plroblem which was never solved by musemaze. Only good workaround is the following and looks very strange. Dont ask me why its working and I also dont like it, but it works. Because opamp input impedance is perfect infinite high it can be done this way and doesn't has any negative impact to the simulation. In real life it must be removed the capacitors! Note: try to avoid crossing the saturation 20V here which will cause again a CFS e.g. load drops, opamp saturates, load increases and opamp will come out of saturation in that very same moment it will cause again a CFS. http://everycircuit.com/circuit/5729377399865344