Django migration error :you cannot alter to or from M2M fields, or add or remove through= on M2M fields

Question

I'm trying to modify a M2M field to a ForeignKey field. The command validate shows me no issues and when I run syncdb :

ValueError: Cannot alter field xxx into yyy they are not compatible types (you cannot alter to or from M2M fields, or add or remove through= on M2M fields)

So I can't make the migration.

class InstituteStaff(Person):
    user                 = models.OneToOneField(User, blank=True, null=True)
    investigation_area   = models.ManyToManyField(InvestigationArea, blank=True,)
    investigation_group  = models.ManyToManyField(InvestigationGroup, blank=True)
    council_group        = models.ForeignKey(CouncilGroup, null=True, blank=True)
    #profiles            = models.ManyToManyField(Profiles, null = True, blank = True)
    profiles             = models.ForeignKey(Profiles, null = True, blank = True)

This is my first Django project so any suggestions are welcome.

Answer 1

I stumbled upon this and although I didn't care about my data much, I still didn't want to delete the whole DB. So I opened the migration file and changed the AlterField() command to a RemoveField() and an AddField() command that worked well. I lost my data on the specific field, but nothing else.

I.e.

migrations.AlterField(
    model_name='player',
    name='teams',
    field=models.ManyToManyField(related_name='players', through='players.TeamPlayer', to='players.Team'),
),

to

migrations.RemoveField(
    model_name='player',
    name='teams',
),
migrations.AddField(
    model_name='player',
    name='teams',
    field=models.ManyToManyField(related_name='players', through='players.TeamPlayer', to='players.Team'),
),