My 2013 MBA has a weird problem: The keyboard is almost unusable, either responding very slowly, not responding at all or producing uncontrollable strings of single characters. The trackpad has similar problems with the cursor only responding very intermittently, or more often not responding at all. An external USB mouse works fine thankfully, and with the on screen keyboard means it is just possible to troubleshoot. Another weird behaviour is the scroll function sometimes comes on locking one at the bottom of a page or list. I have tried the SMC etc chip resets, reinstalled the OS and finally erased the disk and done a factory reinstal, but the problem remains. The problems even manifest in recovery mode, which surprised me. What is really odd, is that these issues are not present on the initial log in screen, indicating that it is not a hardware issue! What I can't figure out is what is special about this login screen? I assumed it was a problem with the individual account, so only manifested once logged in, but as the problem persists in recovery mode that can't be so. I have spent 14 hours working on this but found no solution. Most of my hair now pulled out, so... Any ideas?