I've run into this problem before with Adobe updaters. Generally, as in this time, an error message that the existing version, 9.5.1, has been modified. I would uninstall Reader 9 and start from scratch but there's no uninstaller and, as far as I can see, no current version of the Reader 9 app available on the adobe.com.
(And yes, I have Reader 10 but I don't like it.)
Thanks for that. I see that the last full version of a 9.xx installer (as opposed to an updater) was 9.4.0 and that to get to 9.5.2 I'll have to do 9 updates to the 9.4.0 version. Before starting that, I wonder if I have to fully uninstall 9.5.1. If so, I'm not sure where I will find all the relevant files to discard.
Any ideas? There is no uninstaller that I'm aware of, and I have various other Adobe programs so wouldn't want to throw out the wrong bits.
It is better to install latest Major version of Reader i.e. 10.1.4 from http://get.adobe.com/reader/ . It has got all latest fixes and features.
But if you still want to install Adobe Reader 9.4.0 after uninstalling Reader 9.5.1, delete the following things:
1. Under Application, the whole 'Adobe Reader 9' folder.
2. /Library/Internet Plug-Ins/AdobePDFViewer.plugin
Thanks for that, Nikhil.
(My problem with 10.1.4 is that it doesn't remember non-default print settings, unlike 9.xx - a pain when dealing with multiple docs. And it offers nothing useful to me that 9 lacks.)