Microsoft .NET Framework 3.5 failed to install on Windows computers with the error that the computer cannot download the required files from the Windows Update.

During the Commvault software installation, .NET Framework might fail to install the server roles.

Symptoms

Microsoft .NET Framework 3.5 fails to install on the computers that run Windows Server 2012 (including R2 editions), Windows 8, Windows 8.1, or Windows 10 and reports one of the following errors in the log file:

Error 1

DISM.exe failed to install Server roles with error: -2146498298

Error 2

Failed to install package dotnetfx35role2012 with error code 0x800F0906

Error 3

Failed to install dotnetfx35role2012(dotnetfx35role2012) with error code 0x800F081F

The following GUI error message is displayed:

Failed to install Microsoft .NET Framework 3.5 on the setup. This error may occur because the computer cannot download the required files from Windows Update. To find a solution for the issue, see "Third-Party Software" on the page "Installation Knowledgebase Articles".

Error 4

Failed to install dotnetfx35role2012(dotnetfx35role2012) with error code 0x800F0950

Error 5

Failed to install dotnetfx35role2012(dotnetfx35role2012) with error code 0x800F0954

Causes

During an installation of the Commvault software, the Microsoft .NET Framework 3.5 is installed automatically. Client computers that run certain operating systems might not be able to download the required software files from Windows Update.

Resolution

Refer to the resolutions described in Microsoft support article ".NET Framework 3.5 installation error: 0x800F0906, 0x800F081F, 0x800F0907": https://support.microsoft.com/en-us/help/2734782/.net-framework-3.5-installation-error-0x800f0906,-0x800f081f,-0x800f0907, and then retry the installation.