It takes minutes to open o a file and a good five minutes to save one. It doesn't matter if it is a tiny file or large one. I have spoken for hours and live chatted with adobe agents, even let them take over my computer to find the fault. All to no avail.
I have been using the programme on mac since version 1
Any help would be appreciated.
No one can tell.
Apart from claiming that you have been using Illustrator for a long time there are no relevant informations as to what your problem could be.
Which version of Illustrator are you using?
If that does not help
Did this happen all at once, or slowly over time? Does this happen if you create a new document using the print.ai document profile? Do you have any unusual applications or 3rd party Illustrator plug Ins.
Did you show the hidden folder from Mike's path list? Since 10.7 the User/<yourname>/Library folder has been hidden by default. See here for details