Dynamics GP - "The date cannot be part of a different fiscal year"

http://mystiquesmemory.blogspot.com/2012/03/date-cannot-be-part-of-different-fiscal.html

http://mystiquesmemory.blogspot.com/2016/01/fiscal-period-setup-error-date-cannot.html


In this case we had an issue where the First start day could not be set to 1-Jan-2017 for the 2017 fiscal year. It kept giving us the error  "The date cannot be part of a different fiscal year".

After running a

delete sy40100
where year1=2017
delete SY40101
where YEAR1=2017
delete sy40102
where year1=2017
delete SY40103
where YEAR1=2017

and a

GP>Tools>Utilities>System>Reconcile
the system wiped out the 2005 fiscal periods, and replaced them with the 1-jan-2017 period
This looks like the table got corrupted in some way, and the 2005 values were replaced with 2017 dates

We were able to change the first and last dates for 2005 back to the correct dates through GP, and recalculate the periods.
This freed up the 1-jan-2017 period, and allowed us to recalculate the 2017 year correctly.

A full reconcile was done on the GL, AR and AP for all years from 2005 onward