Hi Maxim

Am new to forums in general and may not be posting right. My apologies if I'm doing so. Will exercise absolute prudence with High Sierra. Thanks there :-).  Have given the Mac to Apple service and hope to get it back within a week. Will use for some time and post subsequently. Also, as suggested by you, will load a typical drawing file. I've quite a few videos recorded so identifying one shouldn't be a problem. My sincere thanks to you and John for your time, help and concern. Have a great weekend.

regards

Shekhar.