There are many ways to make a PDF, and no one solution would fit all of them. So... how EXACTLY do you make a new PDF (what do you click or choose, step by step)? How did you FIRST set the security for the file you were making?
AFAIK Acrobat does not remember PDF passwords internally, unless you are using Actions to secure a batch of PDFs with the same password. But for that you'll have to create an action and then execute it. It is not something that comes per-installed.
As stated, "when saving from Microsoft Excel."
So, I am in Excel, and I choose "Save as PDF" to save the worksheet I am in to a PDF File. I've been doing this for years. I choose "save as PDF", the PDF is created, then immediately opens.
Only recently, after specifically creating a PDF (I'll call it "PDF A") that I *did* want secured with a password, do I now encounter that every file I save as a PDF is now requiring a password... the same password I used for "PDF A".
I set the security on the "PDF A" using the Encrypt > Encrypt with Password option:
I just can't find any way to prevent this from happening on new PDFs I create. They all end up being encrypted with the password I used for "PDF A" .
Update to anyone reading this. I figured out what happened.
The problem originated in Excel / Office and not in Adobe Acrobat directly, where I was looking.
The password was being saved in the Acrobat PDFMaker add-in for Excel (probably any office document) so each time I saved a new file, the password setting was being applied.
To replicate this, go to the Acrobat Tab > Preferences > Security Tab and check the box for "Require a password to open the document" and enter a password.
This preference is sticky, and will be applied to *all* future documents in this office product, until you go in and disable the password requirement by unchecking the box.