Outlook 2007 xp2 lose personal folders connectivity

[thepse]

Hi all,

I have since 2 weeks a strange behavior with my Outlook 2007 clients.
The users's personal folders are on a network drive and the connection is regularly down . so my users needs to shutdown Outlook and Open it again just after a few seconds and they can use their pst file. They can also just close the pst and opent it again and everything is ok during a random time.
Maybe there was a few Outlook updates recently that creates this behavior .??? The network connectivity is good. The OS is Vista SP2 with Outlook 2K7 SP2
Thanks for your returns !!