1. I would like to suggest check the shear force of that elements by doing hand calculations if the error is confirmed then reassign the element after removing it, it works most of the time.

2. Smaller mesh dimensions gives accurate the the analysis. 1.25m is not that abnormal if your floor area is large with respect to it.

3. The floor on which blank mesh appears, subtract that floor then assign it separately and assign the mesh again.

I hope this will help you.

Md. Mohayminul Islam Thank you for the answer, I have tried adding and removing the floor (shell) elements, but I still have some blank spaces within some parts of the floor (shell) mesh.

The problem with these blank spaces in the mesh is that it seems to influence the Shear force (VMAX) values of the floor, increasing it drastically.

I have yet to find a way to solve this problem. Should I change to another software such as MIDAS Gen?

@Lauro Evaristo Teixeira Mota

Following this method i could mange this problem. But one thing I noticed several times that if I edit many times I a evabe file it leads to some others error or get stucked into that error. So sometimes I need to model it fully for second time.

So, if you have time you can do so.

Yeah obviously you can try other applications to justify your work. But just keep in mind that you are doing it exactly same method with same properties. Otherwise, you will get more deviations in result which may confuse you more.

Thank you and whish you will get out of this mess.