While working on a small feature for something at work today I needed to add a field in to one of our domain entities. It really was a tiny change:

public DateTime? LastUpdated { get; private set; }

After continuing on to add unit tests etc I tried to add the migration:

Add-Migration EnabledProjectLastUpdated

This threw a big red error in my face:

Unable to generate an explicit migration because the following explicit migrations are pending: [201311010453495_InitialProduction]. Apply the pending explicit migrations before attempting to generate a new explicit migration.

So I did the logical thing and tried to re build my database locally:

Update-Database

To be greeted by another error:

Unable to update database to match the current model because there are pending changes and automatic migration is disabled. Either write the pending model changes to a code-based migration or enable automatic migration. Set DbMigrationsConfiguration.AutomaticMigrationsEnabled to true to enable automatic migration.
You can use the Add-Migration command to write the pending model changes to a code-based migration.

After going around in circles dropping my localDB, re-attemtping the update and re-attempting the add for rather longer than I'd like to admit I just tried a simple

Add-Migration

For some reason this enabled me to add the Migration when I specified the name and run

update-database

as if nothing had happened. I thought I'd write it down to help anyone else (or myself) if they ran into this.