Offline Gmail can help you read recent correspondence without a connection, but it needs preparation while you are online. The important test is whether the particular messages and attachments needed for your trip are available, not whether the inbox page opens.

Use a trusted computer with the correct mailbox signed in. Google supports offline Gmail in a normal Chrome window, not Incognito. Each account needs its own setup, so enabling it for a personal mailbox does not prepare the work mailbox.

Select and test the working set

In Gmail’s Offline settings, enable offline mail and choose the message period and attachment options that fit the task. Leave Chrome open while the data synchronises. Browser storage availability can limit the offline cache even when the computer appears to have plenty of disk space.

Choose a harmless representative message, an older message near the chosen time boundary and a needed attachment. Once synchronisation finishes, disconnect temporarily and confirm you can find and read them. Offline attachments need to be downloaded and opened in a local application rather than previewed in Gmail.

If a vital old message falls outside the available set, resolve that before travelling. An online search success does not prove the same record will be searchable offline.

Keep drafts distinct from queued mail

Pressing Send while offline is not a way to hold a message for later review. Gmail places it in an Outbox and sends it automatically when the internet returns. Keep unfinished or unapproved replies as drafts instead.

Before reconnecting after a work session, review anything you intentionally queued and make sure its details still make sense. A message composed during an outage may already have been answered by a colleague through another connection.

After the trip, review whether local offline copies are still appropriate for that computer. Plan any removal with outstanding drafts and queued work accounted for; do not clear browser data as an impulsive fix for a message that has not yet synchronised.

References: Gmail offline.