diff --git a/website/upgrade-guides/0-13.html.markdown b/website/upgrade-guides/0-13.html.markdown
index 683d63c91..b14887936 100644
--- a/website/upgrade-guides/0-13.html.markdown
+++ b/website/upgrade-guides/0-13.html.markdown
@@ -39,12 +39,25 @@ may be able to reproduce it and offer advice.
 
 Upgrade guide sections:
 
+* [Before You Upgrade](#before-you-upgrade)
 * [Explicit Provider Source Locations](#explicit-provider-source-locations)
 * [New Filesystem Layout for Local Copies of Providers](#new-filesystem-layout-for-local-copies-of-providers)
   * [Special considerations for in-house providers](#in-house-providers)
 * [Destroy-time provisioners may not refer to other resources](#destroy-time-provisioners-may-not-refer-to-other-resources)
 * [Data resource reads can no longer be disabled by `-refresh=false`](#data-resource-reads-can-no-longer-be-disabled-by--refresh-false)
 
+## Before You Upgrade
+
+When upgrading between major releases, we always recommend ensuring that you
+can run `terraform plan` and see no proposed changes on the previous version
+first, because otherwise pending changes can add additional unknowns into the
+upgrade process.
+
+For this upgrade in particular, completing the upgrade will require running
+`terraform apply` with Terraform 0.13 after upgrading in order to apply some
+upgrades to the Terraform state, and we recommend doing that with no other
+changes pending.
+
 ## Explicit Provider Source Locations
 
 Prior versions of Terraform have supported automatic provider installation only
@@ -137,6 +150,48 @@ run `terraform init` again to re-run the provider installer.
 
 -> **Action:** Either run [`terraform 0.13upgrade`](/docs/commands/0.13upgrade.html) for each of your modules, or manually update the provider declarations to use explicit source addresses.
 
+The upgrade tool described above only updates references in your configuration.
+The Terraform state also includes references to provider configurations which
+need to be updated to refer to the correct providers.
+
+Terraform will automatically update provider configuration references in the
+state the first time you run `terraform apply` after upgrading, but it relies
+on information in the configuration to understand which provider any
+existing resource belongs to, and so you must run `terraform apply` at least
+once (and accept any changes it proposes) before removing any `resource` blocks
+from your configuration after upgrading.
+
+If you are using Terraform Cloud or Terraform Enterprise with the VCS-driven
+workflow (as oposed to CLI-driven runs), refer to
+[The UI- and VCS-driven Run Workflow](/docs/cloud/run/ui.html) to learn how
+to manually start a run after you select a Terraform v0.13 release for your
+workspace.
+
+If you remove a `resource` block (or a `module` block for a module that
+contains `resource` blocks) before the first `terraform apply`, you may see
+a message like this reflecting that Terraform cannot determine which provider
+configuration the existing object ought to be managed by:
+
+```
+Error: Provider configuration not present
+
+To work with null_resource.foo its original provider configuration at
+provider["registry.terraform.io/-/aws"] is required, but it has been removed.
+This occurs when a provider configuration is removed while objects created by
+that provider still exist in the state. Re-add the provider configuration to
+destroy aws_instance.example, after which you can remove the provider
+configuration again.
+```
+
+In this specific upgrade situation the problem is actually the missing
+`resource` block rather than the missing `provider` block: Terraform would
+normally refer to the configuration to see if this resource has an explicit
+`provider` argument that would override the default strategy for selecting
+a provider. If you see the above after upgrading, re-add the resource mentioned
+in the error message until you've completed the upgrade.
+
+-> **Action:** After updating all modules in your configuration to use the new provider requirements syntax, run `terraform apply` to create a new state snapshot containing the new-style provider source addresses that are now specified in your configuration.
+
 ## New Filesystem Layout for Local Copies of Providers
 
 As part of introducing the hierarchical provider namespace discussed in the