Note: This is the recommended solution to configure ArcGIS Desktop to use TLS 1.2. For a description of the other options, see: FAQ: How do I enable TLS 1.2 on ArcGIS Desktop?
As part of improving ArcGIS Online security, Esri requires TLS 1.2 connections for ArcGIS Online services. Action is necessary to ensure access to these services. The methods below describe how to configure ArcGIS Desktop to use TLS 1.2, but do not affect other applications on the system. This is the recommended option for enabling ArcGIS Desktop to use TLS 1.2.
Note: See the Product Life Cycle pages on the Esri Support site for the support status of each released version of ArcGIS Desktop.
Depending on the version of ArcGIS Desktop, use one of the following procedures to configure the application to use TLS 1.2.
Note: After configuring and testing ArcGIS Desktop to use TLS 1.2, return to the Esri Support TLS Page for instructions on how to use TLS 1.2 with other Esri products.
This set of releases uses an earlier version of Microsoft .NET that does not support TLS 1.2.
Note: It is recommended to upgrade to .NET4, and proceed with these steps. However, if upgrading to .NET4 is not feasible, it is necessary to configure the operating system to use TLS 1.2. See: How To: Configure Windows to use TLS 1.2 for ArcGIS Desktop