AutoCAD Message: Non-unitaqry UCS Y axis; normalizing

[Anonymous]

Using AutoCAD 2016.  I had recently created the drawing, closed it and later when I opened it back up, I received this message.  Non-unitaqry UCS Y axis; normalizing.  Every time I hit OK not much happened and then I again received the same message.  I had to use the task manager to exit the drawing.  Then using the Recover drawing utility, I was able to get back into the drawing and it looked as it had previously.  Any thoughts to what may have caused this error?

Thanks!

[Jonathan3891]

Try resting the "UCS" to "World"

[Anonymous]

after hitting the OK several times, I could do a command or two before the message returned.  I did try and change the UCS to "world", "view" and to a Named view.  the only thing that happened is the same message returned.  "Non-unitary UCS Y axis, normalizing.