Mozilla does not officially provide a portable version of Thunderbird. Instead, the most trusted and widely used version is maintained by .
For environments where stability is the top priority, the Thunderbird ESR Portable version is also available. thunderbird portable 64 bit download
You can download the latest stable version from the Thunderbird Portable Edition page at PortableApps.com. Mozilla does not officially provide a portable version
Switching from the older 32-bit standard to 64-bit offers several technical advantages for heavy email users: thunderbird portable 64 bit download