Hi Marianna In case this might be of intererst to you or others - I just ran across a problem relating to Delayed Write Failure errors from Nexis Client. Just upgraded (not a clean install for this particular CPU) the OS X on a MacPro6,2 to High Sierra (10.13.4). Uninstalled all Avid software first and then reinstalled MC2018.4, Nexis 2018.3, Interplay