Problems exporting from iMovie 10.1.12 on High Sierra
Has anybody else experienced problems exporting from iMovie since the update to 'make the library compatible with future versions of Mac OS'? Basically I can't update my system beyond High Sierra and can't afford a new Mac at the moment so I really didn't have an urgent need to change the format of the library and since this was included in the iMovie update I've had nothing but trouble exporting. Things I've done which has brought temporary relief have been resetting the PRAM, booting in Safe Mode then re-booting and in extremis deleting and re-installing iMovie. these have worked in the past but now I can't even get a simple image to export. I have a fair number of YouTube subscribers and its driving me nuts not being able to share new content. any help would be appreciated.
iMac 21.5", macOS 10.13