What specific version of Photoshop? Have you installed all the updates?
What OS version? Have you installed all the OS updates?
OS is Yosemite - 10.10.1
Photoshop CC 2014
Apparently all up to date, and in fact it has been happening since I
changed from another version of Photoshop to this one.
What does the PSErrorLog.txt file in Photoshop's preferences folder say?