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Problem: Firefox + Office 365 + PDF

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Hi, I seem to have found a tricky problem with Firefox 23.0.1, Office 365, and PDF.

After multiple trials, the problem occurs only when I try to attach a PDF to an email (using Office 365) while using Firefox.

After attaching the file to the email, the PDF attachment becomes corrupted.

If I try to open the PDF I created by downloading it back from the email to my desktop I get this Adobe message: "There was an error opening this document. The file is damaged and could not be repaired". The same file, before the uploading process, could be opened smoothly.


1) It happens with all PDFs. No change observed if I use PDFs from other people's computer. No change observed if I save or "print" them from a .DOC version. No change observed if I attach PDF found on the internet (scanned images, documents etc.). In all cases, the problem OCCURS. I tried by attaching other files (.docx) = NO problem observed.

2) It happens only if I download the file back to the desktop or if open the file with Adobe through Firefox after it has been uploaded/attached to the email. I tried opening the file (after it has been uploaded/attached) with the Office 365 preview mode = NO problem observed (I can preview the PDF). I tried opening the file with Adobe Acrobat X Pro = the problem OCCURS. I tried opening the file with Adobe Reader XI = the problem OCCURS. I tried deactivating/reactivating the Firefox Adobe Reader plugin= the problem OCCURS.

3) It happens with Office 365 only. This is the webapp used by my University mail account. I tried with Firefox 23.0.1+ my Hotmail account (which uses a very similar webapp) = NO problem observed. I tried with Firefox 23.0.1+ my Gmail account = NO problem observed.

4) It happens with Firefox 23.0.1 only. I tried using IExplorer + Office 365 account = NO problem occurs I tried using Google Chrome + Office 365 account = NO problem occurs

5) It is a recent issue, probably related with newest Firefox version or newest Office 365. I've updated Firefox few days ago. In the same days the University has upgraded to the latest version of Microsoft Office365. Before the updates no problem had been observed.

My guess: something happens to the PDF file when it goes through Firefox+Office 365 (coding issues?)

I use Windows 7 Home Premium (SP1) 64 BIT

Modified by mm00370

All Replies (1)

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Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

To Enable SafeMode

  • You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
  • Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.
  • Once you get the pop-up, just select "'Start in Safe Mode"

If it works in Safe Mode and in normal mode with all extensions (Tools > Add-ons > Extensions) disabled then try to find which extension is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "Firefox > Exit" (Windows: Firefox/File > Exit; Mac: "Firefox > Quit Firefox"; Linux: "Firefox/File > Quit")