Flattening Form Fields -DC and PC - Windows 10

I regularly produce multipage reports. Only the first page contains form fields. I used to Flatten the form fileds using the Save As Other Optimize function, but that has not worked for me for the last couple of weeks. (So odd!) Is there another method of processing the entire documents to flatten the fields on the first page only. I'm already tired of printint the page as a seperate PDF only to pull it back into the document. 

Thanks in advance for your input. 

Vikki