I’ve been having an issue on my aging Windows XP dev box (yes, I know I should be upgrading to Windows 7, 8 or 10, but with some old legacy systems sometimes that isn’t possible). Sometimes when I single click on a PDF file I’m presented with a dialog box stating that Acrobat Reader has crashed. Because I have development tools on there I’m also prompted to open a debugger. Which is a pain.
While watching in Task Manager I found that simply clicking the PDF file once was enough to launch two instances of AcroRd32.exe which, usually, go away after a short while, or sometimes crash.
The reason for this is that Adobe Reader installs what is called a Shell Handler into Windows (http://msdn.microsoft.com/en-gb/library/windows/desktop/cc144067%28v=vs.85%29.aspx).
When you click a PDF file the Windows shell looks at the handler for that file type and then the shell handler does something (e.g. updates a thumbnail or adds custom columns to the details view in Windows Explorer). If you use a tool such as ShellExView from Nirsoft (http://www.nirsoft.net/utils/shexview.html) you can look at all the shell handlers installed on your PC (both 32 and 64 bit versions are available).
If you’re having problems when you click PDF files or simply don’t want AcroRd32.exe to load each and every time you click a PDF then just load the ShellExView program and look for “PDF Shell Extension” in the “Extension Name” column. There should be about 2 occurrences. Right click on one of them (it doesn’t matter which) and choose “Disable Selected Items”. BOTH items will be disabled.
Just remember that you’ll also lose thumbnail previews of your PDF files as this shell extension does both thumbnails and custom column info in Windows Explorer.
Also, re-installing or updating Adobe Reader is likely to reset this back to “enabled”.
Use the same tool to enable or disable the shell extensions as required. Enabling one will enable both.
Another option is to install a different PDF reader application. There are a few free applications available that do everything Adobe Reader can do and sometimes more:
Foxit Reader (http://www.foxitsoftware.com/Secure_PDF_Reader/)
Nuance PDF Reader (http://www.nuance.co.uk/products/pdf-reader/index.htm)
Nitro PDF Reader (https://www.gonitro.com/pdf-reader)