Just installed the latest version 12.5.1 and I get this error on startup
Access violation at address 0E3A8108 in module ‘oraclient10.dll’. Write of address 00000000
and cannot connect to any Oracle Instance.
Most times we see this it’s one of several possible items: wrong bit size on oracle client (i.e. does not match toad exe bit size), corrupt oracle home settings, multiple Oracle homes and wrong choice on connect screen on which to use. Check these first and then report back if still problems …