Greetings,

I purchased a new, lightning fast computer this week, to replace a six year old system I had. I also purchased Excel 2016, since I no longer had the original 2007 Excel installation disks to install onto the new system.

I've been playing with Excel 2016 now for a couple of days. Almost instantly, I noticed that with Excel 2016, one of my macros that took less than one second to run on my old, slow system using Excel 2007, now took about 26 seconds to run on my new system... with a much faster processor!

WTF?!!

The macro is actually quite simple. It doesn't write to the screen, it doesn't open any files, it doesn't loop through every row on the spreadsheet, etc.

I spent time researching the problem and quickly found out that many others have had the same or similar problems, but none of their suggested solutions worked for me.

However, I finally figured it out on my own. I noticed that if I CLOSE another spreadsheet that I just happened to have open at the same time, the macro would then run almost instantly... also less than one second to run!!

Again, WTF??

So my question is, does anyone know WHY having a second spreadsheet open (that incidentally doesn't contain any macros at all) causes the first spreadsheet's macro to take 26 times longer to run?

The code is much too long to post here. But note that it doesn't access any other spreadsheets or files or anything like that.

Idea: I think it might have something to do with Excel 2016's "feature" that another instance of Excel "appears" to be open, with each spreadsheet you have open. (With Excel 2016, you no longer have the option of having several spreadsheets open in the same window.) I say "appears," in quotes, because only one copy of Excel is actually open.

As always, thanks in advance for any replies.