Flat pattern problem in Solidworks 2016

There is a function o bound you can use. See in the added part

I've inserted the convert solid again and found a problem in the corners.
At the sheet-metal feature, check auto relief, 2mm obround.
Unfold, select face and bends
Make a cutout at the corners so that the plat does not intersect itself
Fold

You're done

Normally you should use the closed corner feature but this feature did not seem to appear.

You began with an block and after that you made your part sheet metal. What you should do is start with a base flange, and then make a milter flange under the angle what you like (select 3 edges at the same time).

You will have more sheet metal features in this way.

I tried it with the mitter flange but as you can see in the file below it doesnt work

the problem is that the plate intersects itself. At the milter flange feature put the gap distance at 6, after that unfold, draw a tab (play with the dimensions, i've tried a little but its not perfect.) and fold to close the gaps.

Try using the correct "custom folding area". Or reduce value of "loss to fold"pict 2. (google translate sorry)