OST(Offline Storage Table) is created by Microsoft Outlook when using an Exchange, IMAP or Microsoft 365 account. It stores a synchronized copy of mailbox data locally, allowing users to access emails without connectivity.
Mozilla Thunderbird is a free, open-source email client that supports multiple email accounts including POP or IMAP. It stores its data in an MBOX file that makes direct import impossible. Thunderbird cannot open or import the OST file directly. So, know the reasons to Convert OST to Thunderbird.
- Comparison Between OST and Thunderbird
- Can You Directly Open an OST File in Thunderbird?
- Reasons to Import OST to Thunderbird
- Manual Methods to Convert OST to Thunderbird
- How to Import OST to Thunderbird via Automated Approach?
- Best Practices for OST to Thunderbird Migration
- Closing Remarks
- Frequently Asked Queries
Comparison Between OST and Thunderbird
| Features | OST | Thunderbird |
| File Format | OST(Offline Storage Table) | MBOX(mailbox |
| Used By | Microsoft Outlook | Thunderbird |
| Purpose | Stores offline copies of Exchange/IMAP data | Store emails locally in plain text format |
| Accessibility | Requires the original Outlook profile | Can be opened in Thunderbird and other email clients |
| Encryption | Encrypted and account specific | Not Encrypted by default |
| Direct Import Support | Cannot be imported into Thunderbird directly | MBOX files can be easily imported into Thunderbird |
| Associated Email Protocols | Exchange, IMAP, or Microsoft 365 | POP3 or IMAP |
| Readability | Not readable outside Outlook | Readable in multiple applications |
Can You Directly Open an OST File in Thunderbird?
No, You cannot open the OST file in Thunderbird directly. Because Thunderbird does not support OST files. Let’s know the reasons of direct import isn’t possible:
- Format Incompatibility: OST files are used by Microsoft Outlook to store offline mailbox data. On the other hand, Thunderbird uses an MBOX file to store mailbox data.
- Encryption and Binding: OST files are linked to a specific Outlook profile and Exchange account, makes them unrecognized to accept OST files.
- Lack of Native Support: Thunderbird has no inbuilt functionality to import OST files.
Reasons to Import OST to Thunderbird
- Many users or organizations want to switch from Microsoft Outlook to Thunderbird to avoid licensing cost and platform independence.
- During this migration, OST to Thunderbird Converter is crucial to retain access to emails.
- Some users deactivate their Exchange or Outlook but save an OST file as a backup file. By importing OST to Thunderbird users can access their previous Outlook data.
- Some organizations adopt Thunderbird due to its flexibility, light weight and compatibility with various email protocols. Employees need to import OST to Thunderbird for continuous work and productivity.
Manual Methods to Convert OST to Thunderbird
If you have configured both Thunderbird and Outlook account then you can follow the process as we have explained below:
- First, open Thunderbird and click on the menu.
- After that, click on Tools and press on Import.
- Select Import Account, Address book and Messages from Outlook.
- Click on the Continue button and check on Account Settings, Address Book, and Mail Messages.
- After clicking on continue, click on Start Import to begin import OST to Thunderbird.
Demerits of Manual Method
- This process only works on Windows systems where both Outlook and Thunderbird are installed and configured. It won’t work on Mac or Linux.
- You must have access to a working Outlook profile with the OST file already linked to it. If OST is orphaned(or Outlook data file cannot accessed), this approach will fail.
- This method does not allow importing all data, especially large mailboxes, attachments, calendars or some folder structure will not be preserved.
- If an OST file is orphaned or corrupted then this approach will not work as it does not offer any inbuilt feature to restore and convert a corrupted OST file.
How to Import OST to Thunderbird via Automated Approach?
If you have only an OST file without a configured Outlook account then we recommend you to choose Jagware OST to Thunderbird Converter as this software offers direct import in Thunderbird and also offers a maintained file structure same as appears in Outlook. To use this utility, you just need to click on download button and follow the process as we have explained below:
Simple Instructions to Import OST to Thunderbird
- First, Download and run Automated Tool on your system.
- Click on Convert configured Outlook mailbox data and press Next.
- Preview to select the OST mailbox folder as you want to import.
- Choose Thunderbird in the list of Saving options.
- Use filter options to select crucial data and stay away from unwanted files.
- Press Convert button to start Import OST to Thunderbird.
Remarkable Features of Automated Software
- This software can also convert OST to PST, PDF, PST, EML, MSG, GIF, PNG, JPEG, BMP and 28+ Saving feature..
- It also offers advanced filters such as date range, from, to, subject, exclude folders, organizer, root folder, exclude empty folder, mails, calendars, contacts, create exception log and many more.
- This tool can easily restore and convert corrupted, oversize, dismounted, and inaccessible OST files.
- You can convert OST emails, contacts, calendars, attachments, notes, tasks and all other data contained in an OST file.
- With this wizard, you can also import OST to Microsoft 365, Gmail, Yahoo, IBM Verse, and all IMAP Supported email servers.
Best Practices for OST to Thunderbird Migration
- Always take backup of the OST file before beginning the migration to prevent accidental data loss.
- Follow the process correctly to prevent data loss or file corruption.
- After conversion, Verify emails, attachments, formatting and other OST data has been transferred correctly.
Closing Remarks
Let’s conclude this guide by summarizing all crucial information to import OST to Thunderbird. We have explained both manual and automated approaches to address this query. As manual approaches are free, but it may transfer partial OST data and important attributes like formatting or attachments may not be preserved. If you don’t want to take any risk with your OST files, we recommend using automated tool as its expert trusted solution and especially valuable for handling large or multiple OST files with complete accuracy and reliability.
Frequently Asked Queries
What program opens OST files?
Microsoft Outlook opens OST files when connected to the original account. If Outlook isn’t available then you can opt Free OST Viewer to access data without the original profile.
Can Thunderbird open ICS files?
Yes, Thunderbird can open and import ICS(iCalendar) files. You can import calendar events by going to the Calendar tab and using the Import option to load ICS files into your Thunderbird folder.
What file format does Thunderbird Use?
Thunderbird uses the MBOX file to store email messages and an ICS file used for calendar data. Each email folder is saved as a separate MBOX file containing all messages in that folder.
