Windows Server 2019 build 17666

10.0.17666.1000.rs_prerelease.180504-1504
	Build of Windows Server 2019
OS family	Windows 10 (NT 10.0)
Version number	10.0
Build number	17666
Build revision	1000
Architecture	x64
Build lab	rs_prerelease
Compiled on	2018-05-04
Expiration date
Timebomb	2018-12-14 (+224 days)
SKUs
	Standard Server; Standard Server Core; Datacenter Server; Datacenter Server Core
About dialog

Windows Server 2019 build 17666 is the fourth Insider Preview build of Windows Server 2019. It was released on 15 May 2018.

New features and changes[edit | edit source]

Improved the Get-ClusterPerformanceHistory cmdlet to be more scripting-friendly. You can now pipe performance history into utility cmdlets like Sort-Object, Where-Object and Measure-Object. These cmdlets let the user quickly find the average or peak value, filter values, plot trend lines, run outlier detection, and other features.
Added performance history for the Storage Spaces cache for reads (% hit rate) and writes (% full), as well as the CSV in-memory read cache (% hit rate). These new series are available per-server and in aggregate.
Some performance history series have changed names in this build for more clarity and consistency - for example, Node.Cpu.Usage is now ClusterNode.Cpu.Usage.
Added some new PowerShell cmdlets for the management of volumes with delimited allocation. These include Get-StorageScaleUnit, used to see fault domains, and Get-VirtualDisk to see the disk's current allocation; and set or modify allocation by using friendly names for fault domains.
Extended the timebomb to 14 December 2018.

The size of a file according to NTFS and a stream control block can become different from the size according to Cache Manager. This can cause the system to crash if a read operation is out of bounds for the file size that Cache Manager has stored.
Active Directory domain controllers may not upgrade correctly during an in-place OS upgrade.
If you create or edit a policy for AppLocker, the associated MMC snap-in can crash when generated rules for a packaged app.
After an upgrade, the AppX database may have corrupted entries, which can cause problems for components that use said entries.