I've found this software very useful and have just upgraded my Mac from Snow Leopard 10.6.8 to El Capitan 10.11.6.
On opening Acrobat when editing for example creating a line or box when I attempt to define properties Acrobat crashes.
Tried it many times with no success, however creating a PDF from multiplies seems to work.
Is there an upgrade available or how can I solve this problem.
When you upgrade Mac OS it's important that you check compatibility of all your apps. You may need to budget for a complete new purchase as in this case. It is too late for reduced price upgrades to Acrobat 9 and older versions. The current version is Acrobat Pro DC: subscriptions strongly recommended over permanent purchase. Don't buy an upgrade - it won't work with your older product.