Merging and downloaded docs look okay and then go blank in parts after a while.

Good morning Dave,

All three employees that are having the issue are using Windows 2010.    They were all at first using the licensed version  of Adobe Acrobat Pro DC 2015 release which has worked fine for 5 years.  About a month ago our new HR files started to show blank or what looked like half a page.  Almost as if they were being scanned and the page was pulled away after half a scan.  We are acquiring these documents to be merged in three ways.  One is scanning of hard copies to the server prior to shredding them, two they are downloaded from the Deltek/CostPoint, and three is where documents are downloaded from talent management.  The single files are saved to our file server as PDFs and look fine.  They can be opened and read and if needed edited and saved and read agian.  After they are merged when needed, same thing, they can be read.  But for some reason over time, being a day, week, or month, when they are opened there are blank pages interspursed within the document or pages where there is only half a page again like a half scan.  Our solution, we thought, was to buy the latest Adobe Pro via online subscription.  Great program, but this did not work.  So I called Adobe yesterday afternoon and they said to go to Help in the Adobe App and select repair installation.  All three users have done this and have created new merged PDFs.  Waiting to see if they get corrupted.  I read some where that it could be a setting on our server.  Something about the server being set to use "Replace" when using network drives instead of using"Update"?  I can look at that, but our Group Policy has not been changed in two years.  Unfortunately, all the docs have PII or sensitive data so I can post one.

v/r,

Dave