Synkronizer is described as 'allows you to compare calculation models, data bases, lists or whole Excel spreadsheets automaticallly. Differences are highlighted and can be aligned. If desired, Synkronizer allows you to merge your spreadsheets'. There are six alternatives to Synkronizer for Windows. The best alternative is DiffEngineX. It's not free, so if you're looking for a free alternative, you could try Spreadsheet Compare. Other great apps like Synkronizer are Spreadsheet Advantage (Paid), Excel Compare (Paid), xlCompare (Paid) and PerfectXL Compare (Paid).
DiffEngineX is a fast utility that finds the differences between the formulae, constants, defined names, cell comments and Visual Basic code contained in either two whole Excel workbooks (*.xls, *.xlsx, *.xlsm, *.xlsb) or selected worksheets.
This is a tool developed by a small team in the Netherlands. It's a standalone application that generates a simple, concise, easy to understand overview of the differences between 2 Excel sheets. It can also handle even the most complex Excel files.