What is the SRS file format?
OUTLOOK.SRS is the Send/Receive Settings file created by Microsoft Outlook to store all Send/Receive group configuration. The .srs file records the scheduling rules that govern how and when Outlook communicates with email servers - including polling intervals for each account, which folders to include or exclude during synchronization, and whether to send queued messages at each scheduled interval.
The file is stored in a proprietary binary format at %APPDATA%\Microsoft\Outlook\Outlook.srs and is managed entirely through Outlook's user interface: File → Options → Advanced → Send/Receive (in older versions: Tools → Send/Receive → Send/Receive Settings). Direct editing of the .srs file is not supported or necessary.
If the file is deleted or becomes corrupted, Outlook recreates it automatically with default settings on next launch - accidental deletion is not catastrophic, though any custom Send/Receive groups will need to be reconfigured. The .srs file is tied to a specific Outlook major version and is not forward-compatible across version upgrades.
Related files include .pst (personal message store) and .ost (offline data cache), which hold actual email data. The .srs file holds only scheduling and account configuration - no messages, contacts, or calendar items are stored in it.
Security & safety
RISK: LOWConfiguration file only - no executable content, no personal email data. Contains server addresses and polling intervals but not passwords or email content.
Format details
in a nutshell- SubRip Subtitle File - .srs is also used informally (rarely) as a subtitle-related extension, though .srt is the standard SubRip extension.
Programs that open SRS files
Windows2 apps
Microsoft Outlook
Paid Manage settings via: File → Options → Advanced → Send/Receive, or Tools → Send/Receive → Send/Receive Settings → Define Send/Receive Groups. 
Microsoft Office (suite)
Paid Included with Microsoft 365 / Office 2019+; open Outlook then manage via Send/Receive settings. Technical details
deep spec| Format type | Proprietary binary settings/configuration file |
| Encoding | Binary, little-endian |
| Default filename | Outlook.srs |
| Default location | %APPDATA%\Microsoft\Outlook\ |
| Content | Send/Receive group definitions, account polling intervals, folder inclusion/exclusion rules, send behavior per account |
| Platform | Windows only |
| Typical file size | 4 KB - 64 KB |
| Version compatibility | Tied to Outlook major version; not forward-compatible across major releases |
| Managed via | Outlook UI: File → Options → Advanced → Send/Receive (or Tools → Send/Receive in older versions) |
| Recovery behavior | If deleted or corrupted, Outlook recreates the file with default settings on next launch |
| Content scope | Configuration only - no email messages, contacts, or calendar data |
| Compatible versions | Outlook 2000 through Microsoft 365 |
| Released | Microsoft Outlook 2000 (circa 2000) |
| Latest version | Compatible with Outlook 2019/Microsoft 365; format largely unchanged |
Community Q&A
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