If the /export directory is near full capacity when you upgrade to the Solaris 10 release, space requirements for /export are miscalculated. The upgrade then fails. This problem commonly occurs if a diskless client is installed. Another instance of when the problem occurs is when third-party software is installed in the /export directory. The following message is displayed:
WARNING: Insufficient space for the upgrade.
Workaround: Before you upgrade, choose one of the following workarounds:
Rename the /export directory temporarily, until the upgrade is completed.
Temporarily comment out the /export line in the /etc/vfstab file until the upgrade is completed.
If /export is a separate file system, then unmount /export before you perform the upgrade.