I tried the simple test case in this discussion, and in the Win 10 Ent 21H1 environment it takes 9 minutes between "Start CFSPREADSHEETWRITE" and "End CFSPREADSHEETWRITE".
By @Legorol

9 minutes! Wow! This is then a thing.
Have you experimented by writing to a different file path?
What happens when you run the tag version of the code?
Could you too share the content of your jvm.config file (Obfuscate any private or sensitive information with ***).
Does either of you use FusionReactor? If so, could you share the "profiler" log for this request.
While we look into it, could you or @michaelh53276323, in the meantime, create a bug ticket. Please let us know when you do.
Hi, i hope you had nice christmas! 🙂
I found my problem, for that a little bit of history.
I installed CF2021 at the end of June of 2021 with the installer timestamp 20th march 2021.
Than i changed java to 12.0.2, that i found of highest specification.
Over the time i install Update 1,2,3.
The system runs well until the CFSPREADSHEETWRITE problem.
The rest of the story is written above.
Now i compare every files and restore the java.home to {application.home}/jre.
I compare the JRE folder with the JRE folder of my out of the box laptop with my fresh downloaded installer with timestamp 3th september 2021.
Every files are different.
I overwrite JRE-files from fresh to old JRE-files of old installation. Voila, it works.
I go back to java12.0.2 inside jvm.config and the same time problem is in town.
On my way to the deepness of CF i have to say many many many thanks for your support, patience and help me for repair this problem.
Everyone, have a good New Year! To an exciting 2022... 🙂