You need to have an access to your mailbox while you haven't any internet connection (train, hotels...) ? Here is the solution which replaces Thunderbird.
Warning, before everything, you have to know that the copy of your mails between the online and the offline modes can last 10 minutes.
Google brings you an offline mode via its browser Chrome.
This tool has been chose by the Oxylane IT teams as the offline mode.
Here is the process to install this tool :
To be able to use the offline mode, you must have Google Chrome read your mails with it.
(You can download resource from Internet)
The Gmail offline mode
To install the Gmail offline mode, you have just to launch Google Chrome which is now available in "Programs" of your start menu and to go to this url : https://chrome.google.com/webstore/detail/ejidjjhkpiempkbhmpbfngldlkglhimk?hl=en-US&hc=hp&hcp=new
In the window which appears, click on "Install".
You will see that a new icon will appear. To launch the offline mode, You have just to open a new tab by clicking on the little "+" over the url bar and to click on the Offline Googl... icon.
After the first launch, you will get a message to accept offline mode.
Some answers to your questions :
* The first time that you launch the offline mode, it may take some time to sync your mails.
* The offline mode only sync 3 days of mails and the starred mails.
* No need to have an opened tab with the offline mode, it will automatically work as a background task in Google Chrome.
* Warning, the interface changes between the online and the offline mode.
The Calendar offline mode
to configure the offline mode, go on your Google calendar and click on the little cogwheel at the top right. Select then "Offline mode".
A window opens to ask you if you want to install the offline mode, click then on "Install from the Web Store".
You will be redirected on the Google Web Store directly on the calendar page. Click then on "Add to Google Chrome".
Then in the window which opens, click on "Install".
When you open a new tab, a calendar icon should appear. Click on it to be brought to the Google Calendar.
You can check if it is installed by clicking another time on the cogwheel and by checking if a little green sign has appeared near to the "Offline mode" link.
To use it, you've just to go on your calendar at the following url : http://www.google.com/calendar.
Google will be able to recognize if you avec a connection or not and will directly switch between the online and offline mode.