Juniper Allegro CE Owner's Manual page 154

Avoiding Unresolved Files through File Synchronization
When connecting multiple Allegros to a desktop PC, it is important
that they do not experience unresolved files in ActiveSync. If this
situation occurs, it continues the current ActiveSync connection with
the Allegro and MultiSync is not be able to disconnect. If the Allegro
is unable to disconnect, the other Allegros can't connect and
synchronize their files with the desktop PC.
To prevent this from happening, you must set up which device has
the master file, the Allegro or desktop PC. This must be set up in
ActiveSync and in each Allegro partnership. To do this, open
ActiveSync and complete the following steps:
1) Select Tools|Options.
2) Click on the Rules tab on the Options screen.
3) Select either the Always replace the item on my device setting or the
Always replace the item on this computer setting in the Conflict
Resolutions box on the Options screen:
Page 4-94 Windows CE