Did this error message appear, "Unable to complete orientation. N photos have oriented correctly (#s:<photo list>) and M have not been oriented (#:<photo list>). Suggestion: try Point Audit Selected to see if 3 or more points are shared between the oriented set and the unoriented sets of photos."? If so then there is a scale failure.
Did this error message appear (i.e. scaling failed)?
Yes - Scaling Failed (see below).
If you did not get the scale error message shown above then the next step is to determine why orientation failed. The best way to do this is to reduce the project to orientations of sets of two photographs. You use the processing actions in Photo Properties to process only some subset of the photos. Process the new pair-photo project and check the result in the 3D Viewer. If the result looks OK, pick another pair and repeat. Note when you pick pairs, pick photos that share at least 6 points.
Did you find a pair of photographs that will not orient correctly?
Yes - One or More Pairs will not Orient (see below)
No - All pairs Orient Successfully (see below)