Optimize excel vba code run faster

We are a startup company making silicon hardware. Thousands of devices are fabricated on silicon wafers, and those devices need to be measured individually. We use an Excel VBA script to generate a table from some input tables, which eventually is used for controlling a measurement robot. This vba script used to work fine with an old version of excel (5 years ago or so) but does hang or executes very slowly with new excel (2016, version 1807). The vba runs two nested for loops over two ranges defined on two sheets of the excel file and writes out cells in another sheet. Two example files are provided: • one that runs ok (in some 10 secs on my thinkpad x230 i5 processor) • one that runs very slowly or fully hangs excel The slow-down problem of excel is related to how many iterations the loops go through, but this does not go proportionally to the number of iterations - there seems to be some threshold. The whole windows (7) operating system slows down when excel struggles with the vba code, so could it be some sort of system call problem? It also seems that excel does not consume very much of memory or processing power. Please look at the files and the excel code within. Run the VBA code by clicking the button "Create config sheet" on the "device_listing" sheet. The difference in the files is that in the one that runs slowly or hangs, "wafermap_64groups" has a larger selection of bolded cells which means more iterations in nested for loops. This can be an easy problem to solve for somebody with experience on VBA and it might not take more than 10 minutes for you. €100 is offered for the task.