-->

1. Error Code 17900 Outlook For Mac
2. Outlook Error Code 17900
3. Outlook Error Code 17900

Applies to:

To, resolve this synchronize the OLM with the server or reset it. Start the Outlook for Mac application (if it is possible to open) Go to Menu, then select preferences and click on Sync Services. Uncheck all boxes and Restart Outlook in Mac. Reset the sync preferences to Fix Outlook synchronization problem. The issue occurs on MS Outlook for Windows, MS Outlook for Mac, and Mail app for iOS. The chances that all three clients have issues at the same time are pretty slim. It seems to be more of an issue on the server side (incoming and outgoing ports).

• Microsoft Defender Antivirus

Keeping Microsoft Defender Antivirus up to date is critical to assure your devices have the latest technology and features needed to protect against new malware and attack techniques. Make sure to update your antivirus protection, even if Microsoft Defender Antivirus is running in passive mode. There are two types of updates related to keeping Microsoft Defender Antivirus up to date:

• Security intelligence updates
• Product updates

Tip

To see the most current engine, platform, and signature date, visit the Security intelligence updates for Microsoft Defender Antivirus and other Microsoft antimalware

Security intelligence updates

Microsoft Defender Antivirus uses cloud-delivered protection (also called the Microsoft Advanced Protection Service or MAPS) and periodically downloads security intelligence updates to provide protection.

Note

Updates are released under the below KB numbers:

• Microsoft Defender Antivirus: KB2267602
• System Center Endpoint Protection: KB2461484

Cloud-delivered protection is always on and requires an active connection to the Internet to function. Security intelligence updates occur on a scheduled cadence (configurable via policy). For more information, see Use Microsoft cloud-provided protection in Microsoft Defender Antivirus.

For a list of recent security intelligence updates, see Security intelligence updates for Microsoft Defender Antivirus and other Microsoft antimalware.

Engine updates are included with security intelligence updates and are released on a monthly cadence.

Product updates

Microsoft Defender Antivirus requires monthly updates (KB4052623) known as platform updates.

You can manage the distribution of updates through one of the following methods:

• The usual method you use to deploy Microsoft and Windows updates to endpoints in your network.

For more information, see Manage the sources for Microsoft Defender Antivirus protection updates.

Note

• Monthly updates are released in phases, resulting in multiple packages visible in your Window Server Update Services.
• This article lists changes that are included in the broad release channel. See the latest broad channel release here.
• To learn more about the gradual rollout process, and to see more information about the next release, see Manage the gradual rollout process for Microsoft Defender updates.
• To learn more about security intelligence updates, see Security intelligence updates for Microsoft Defender Antivirus and other Microsoft antimalware.

Monthly platform and engine versions

For information how to update or install the platform update, see Update for Windows Defender antimalware platform.

All our updates contain

• performance improvements;
• serviceability improvements; and
• integration improvements (Cloud, Microsoft 365 Defender).
  

 Security intelligence update version: 1.345.13.0
 Released: August 5, 2021
 Platform: 4.18.2107.4
 Engine: 1.1.18400.4
 Support phase: Security and Critical Updates

What's new

• Device control support added for Windows Portable Devices
• Potentially unwanted applications (PUA) protection is turned on by default for consumers (See Potentially unwanted apps will be blocked by default)
• Scheduled scans for Group Policy Object managed systems will adhere to user configured scan time
• Improvements to the behavior monitoring engine

Known Issues

No known issues

 Security intelligence update version: 1.343.17.0
 Released: June 28, 2021
 Platform: 4.18.2106.5
 Engine: 1.1.18300.4
 Support phase: Security and Critical Updates

What's new

• New controls for managing the gradual rollout process of Microsoft Defender updates. See Manage the gradual rollout process for Microsoft Defender updates.
• Improvement to the behavior monitoring engine
• Improvements to the rollout of antimalware definitions
• Extended Edge network event inspections

Known Issues

No known issues

 Security intelligence update version: 1.341.8.0
 Released: June 3, 2021
 Platform: 4.18.2105.4
 Engine: 1.1.18200.4
 Support phase: Security and Critical Updates

What's new

• Improvements to behavior monitoring
• Fixed network protection notification filtering feature

Known Issues

No known issues

Previous version updates: Technical upgrade support only

After a new package version is released, support for the previous two versions is reduced to technical support only. Versions older than that are listed in this section, and are provided for technical upgrade support only.

 Security intelligence update version: 1.337.2.0
 Released: April 26, 2021 (Engine: 1.1.18100.6 released May 5, 2021) Platform: 4.18.2104.14
 Engine: 1.1.18100.5
 Support phase: Technical upgrade support (only)

What's new

• Additional behavior monitoring logic
• Improved kernel mode key logger detection
• Added new controls to manage the gradual rollout process for Microsoft Defender updates

Known Issues

No known issues

 Security intelligence update version: 1.335.36.0
 Released: April 2, 2021
 Platform: 4.18.2103.7
 Engine: 1.1.18000.5
 Support phase: Technical upgrade support (only)

What's new

• Improvement to the Behavior Monitoring engine
• Expanded network brute-force-attack mitigations
• Additional failed tampering attempt event generation when Tamper Protection is enabled

Known Issues

No known issues

 Security intelligence update version: 1.333.7.0
 Released: March 9, 2021
 Platform: 4.18.2102.3
 Engine: 1.1.17900.7
 Support phase: Technical upgrade support (only)

What's new

• Improved service recovery through tamper protection
• Extend tamper protection scope

Known Issues

No known issues

 Security intelligence update version: 1.327.1854.0
 Released: February 2, 2021
 Platform: 4.18.2101.9
 Engine: 1.1.17800.5
 Support phase: Technical upgrade support (only)

What's new

• Shellcode exploit detection improvements
• Increased visibility for credential stealing attempts
• Improvements in antitampering features in Microsoft Defender Antivirus services
• Improved support for ARM x64 emulation
• Fix: EDR Block notification remains in threat history after real-time protection performed initial detection

Known Issues

No known issues

 Security intelligence update version: 1.327.1854.0
 Released: December 03, 2020
 Platform: 4.18.2011.6
 Engine: 1.1.17700.4
 Support phase: Technical upgrade support (only)

What's new

• Improved SmartScreen status support logging

Known Issues

No known issues

 Security intelligence update version: 1.327.7.0
 Released: October 29, 2020
 Platform: 4.18.2010.7
 Engine: 1.1.17600.5
 Support phase: Technical upgrade support (only)

What's new

• New descriptions for special threat categories
• Improved emulation capabilities
• Improved host address allow/block capabilities
• New option in Defender CSP to Ignore merging of local user exclusions

Known Issues

No known issues

 Security intelligence update version: 1.325.10.0
 Released: October 01, 2020
 Platform: 4.18.2009.7
 Engine: 1.1.17500.4
 Support phase: Technical upgrade support (only)

What's new

• Admin permissions are required to restore files in quarantine
• XML formatted events are now supported
• CSP support for ignoring exclusion merges
• New management interfaces for:
  • UDP Inspection
  • Network Protection on Server 2019
  • IP Address exclusions for Network Protection
• Improved visibility into TPM measurements
• Improved Office VBA module scanning

Known Issues

No known issues

 Security intelligence update version: 1.323.9.0
 Released: August 27, 2020
 Platform: 4.18.2008.9
 Engine: 1.1.17400.5
 Support phase: Technical upgrade support (only)

What's new

• Add more telemetry events
• Improved scan event telemetry
• Improved behavior monitoring for memory scans
• Improved macro streams scanning
• Added AMRunningMode to Get-MpComputerStatus PowerShell cmdlet
• DisableAntiSpyware is ignored. Microsoft Defender Antivirus automatically turns itself off when it detects another antivirus program.

Known Issues

No known issues

 Security intelligence update version: 1.321.30.0
 Released: July 28, 2020
 Platform: 4.18.2007.8
 Engine: 1.1.17300.4
 Support phase: Technical upgrade support (only)

What's new

• Improved telemetry for BITS
• Improved Authenticode code signing certificate validation

Known Issues

No known issues

 Security intelligence update version: 1.319.20.0
 Released: June 22, 2020
 Platform: 4.18.2006.10
 Engine: 1.1.17200.2
 Support phase: Technical upgrade support (only)

What's new

• Possibility to specify the location of the support logs
• Skipping aggressive catchup scan in Passive mode.
• Allow Defender to update on metered connections
• Fixed performance tuning when caching is disabled
• Fixed registry query
• Fixed scantime randomization in ADMX

Known Issues

No known issues

 Security intelligence update version: 1.317.20.0
 Released: May 26, 2020
 Platform: 4.18.2005.4
 Engine: 1.1.17100.2
 Support phase: Technical upgrade support (only)

What's new

• Improved logging for scan events
• Improved user mode crash handling.
• Added event tracing for Tamper protection
• Fixed AMSI Sample submission
• Fixed AMSI Cloud blocking
• Fixed Security update install log

Known Issues

No known issues

 Security intelligence update version: 1.315.12.0
 Released: April 30, 2020
 Platform: 4.18.2004.6
 Engine: 1.1.17000.2
 Support phase: Technical upgrade support (only)

What's new

• WDfilter improvements
• Add more actionable event data to attack surface reduction detection events
• Fixed version information in diagnostic data and WMI
• Fixed incorrect platform version in UI after platform update
• Dynamic URL intel for Fileless threat protection
• UEFI scan capability
• Extend logging for updates

Known Issues

No known issues

 Security intelligence update version: 1.313.8.0
 Released: March 24, 2020
 Platform: 4.18.2003.8
 Engine: 1.1.16900.4
 Support phase: Technical upgrade support (only)

What's new

• CPU Throttling option added to MpCmdRun
• Improve diagnostic capability
• reduce Security intelligence timeout (5 min)
• Extend AMSI engine internal log capability
• Improve notification for process blocking

Known Issues

[Fixed] Microsoft Defender Antivirus is skipping files when running a scan.

 Security intelligence update version: 1.311.4.0
 Released: February 25, 2020
 Platform/Client: -
 Engine: 1.1.16800.2
 Support phase: Technical upgrade support (only)

What's new

Known Issues

No known issues

Security intelligence update version: 1.309.32.0
Released: January 30, 2020
Platform/Client: 4.18.2001.10
Engine: 1.1.16700.2
 Support phase: Technical upgrade support (only)

What's new

• Fixed BSOD on WS2016 with Exchange
• Support platform updates when TMP is redirected to network path
• Platform and engine versions are added to WDSI
• extend Emergency signature update to passive mode
• Fix 4.18.1911.3 hang

Known Issues

[Fixed] devices utilizing modern standby mode may experience a hang with the Windows Defender filter driver that results in a gap of protection. Affected machines appear to the customer as having not updated to the latest antimalware platform.

Important

This update is:

• needed by RS1 devices running lower version of the platform to support SHA2;
• has a reboot flag for systems that have hanging issues;
• is re-released in April 2020 and will not be superseded by newer updates to keep future availability;
• is categorized as an update due to the reboot requirement; and
• is only be offered with Windows Update.
  

Security intelligence update version: 1.307.13.0
Released: December 7, 2019
Platform: 4.18.1911.3
Engine: 1.1.17000.7
Support phase: No support

What's new

• Fixed MpCmdRun tracing level
• Fixed WDFilter version info
• Improve notifications (PUA)
• add MRT logs to support files

Known Issues

When this update is installed, the device needs the jump package 4.18.2001.10 to be able to update to the latest platform version.

Microsoft Defender Antivirus platform support

Platform and engine updates are provided on a monthly cadence. To be fully supported, keep current with the latest platform updates. Our support structure is dynamic, evolving into two phases depending on the availability of the latest platform version:

• Security and Critical Updates servicing phase - When running the latest platform version, you will be eligible to receive both Security and Critical updates to the anti-malware platform.

• Technical Support (Only) phase - After a new platform version is released, support for older versions (N-2) will reduce to technical support only. Platform versions older than N-2 will no longer be supported.*

* Technical support will continue to be provided for upgrades from the Windows 10 release version (see Platform version included with Windows 10 releases) to the latest platform version.

During the technical support (only) phase, commercially reasonable support incidents will be provided through Microsoft Customer Service & Support and Microsoft's managed support offerings (such as Premier Support). If a support incident requires escalation to development for further guidance, requires a non-security update, or requires a security update, customers will be asked to upgrade to the latest platform version or an intermediate update (*).

Platform version included with Windows 10 releases

The below table provides the Microsoft Defender Antivirus platform and engine versions that are shipped with the latest Windows 10 releases:

For Windows 10 release information, see the Windows lifecycle fact sheet.

Updates for Deployment Image Servicing and Management (DISM)

We recommend updating your Windows 10 (Enterprise, Pro, and Home editions), Windows Server 2019, and Windows Server 2016 OS installation images with the latest antivirus and antimalware updates. Keeping your OS installation images up to date helps avoid a gap in protection.

For more information, see Microsoft Defender update for Windows operating system installation images.

 Package version: 1.1.2108.01
 Platform version: 4.18.2107.4
 Engine version: 1.1.18300.4
 Signature version: 1.343.2244.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2107.02
 Platform version: 4.18.2105.5
 Engine version: 1.1.18300.4
 Signature version: 1.343.658.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2106.01
 Platform version: 4.18.2104.14
 Engine version: 1.1.18100.6
 Signature version: 1.339.1923.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2105.01
 Platform version: 4.18.2103.7
 Engine version: 1.1.18100.6
 Signature version: 1.339.42.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2104.01
 Platform version: 4.18.2102.4
 Engine version: 1.1.18000.5
 Signature version: 1.335.232.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2103.01
 Platform version: 4.18.2101.9
 Engine version: 1.1.17800.5
 Signature version: 1.331.2302.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2102.03
 Platform version: 4.18.2011.6
 Engine version: 1.1.17800.5
 Signature version: 1.331.174.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2101.02
 Platform version: 4.18.2011.6
 Engine version: 1.1.17700.4
 Signature version: 1.329.1796.0

Fixes

• None

Error Code 17900 Outlook For Mac

Additional information

• None
  

 Package version: 1.1.2012.01
 Platform version: 4.18.2010.7
 Engine version: 1.1.17600.5
 Signature version: 1.327.1991.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2011.02
 Platform version: 4.18.2010.7
 Engine version: 1.1.17600.5
 Signature version: 1.327.658.0

Fixes

• None

Outlook Error Code 17900

Additional information

• Refreshed Microsoft Defender Antivirus signatures
  

 Package version: 1.1.2011.01
 Platform version: 4.18.2009.7
 Engine version: 1.1.17600.5
 Signature version: 1.327.344.0

Fixes

• None

Additional information

• None
  

 Package version: 1.1.2011.01
 Platform version: 4.18.2008.9
 Engine version: 1.1.17400.5
 Signature version: 1.327.2216.0

Fixes

• None

Additional information

• Added support for Windows 10 RS1 or later OS install images.
  

Additional resources

Outlook Error Code 17900