AWS Toolkit extension does not appear in the Visual Studio Extension Manager

## Symptoms

After installing the AWS Toolkit extension, your instance of Visual Studio can get in a state where the Extension Manager does not list the AWS Toolkit extension under the list of Installed extensions.

Afterwards, you might have some of the following behaviors:

* you see the AWS Explorer, and are able to use it (also, under the “View” menu, you see the “AWS Explorer” menu item)
* when you try to install the extension, you are shown a message stating that it is already installed

## Solution

Visual Studio has released a fix as part of version 17.11.5 to help with this issue.

1. Install the latest version of Visual Studio 2022. You need to update to version 17.11.5 at a minimum.
1. Close all running instances of Visual Studio.
1. Open the Developer Command Prompt as an Administrator.
1. Run the following command: `devenv /updateconfiguration /resetExtensions`
1. Wait for the command to finish executing.
1. Restart Visual Studio.
1. The extension should now be listed as installed, and the AWS Extension should no longer report one of the error messages listed at the top of this issue.

This guidance comes from the [Visual Studio Developer Community](https://developercommunity.visualstudio.com/t/MEF-component-issues-with-AWS-Toolkit-wi/10702310#TPIN-N10763706-N10764754).

Additional solutions

Here are some actions you can run to try to bring Visual Studio back into a good state.

### Have Visual Studio re-generate some of its internal cache files

It is possible that some of Visual Studio's internal bookkeeping got out of sync when an extension is installed. Visual Studio will rebuild these files the next time you launch Visual Studio.

- Close all instances of Visual Studio
- Navigate to `%localappdata%\Microsoft\VisualStudio`
- Locate the folder corresponding with your Visual Studio 2022 installation. It will start with "17.0_". Go into this folder
- Make a backup copy of `privateregistry.bin` elsewhere, then delete this file.
- Navigate to the `Extensions` subfolder
- Make a backup copy of `ExtensionMetadata.mpack` elsewhere, then delete this file.
- Launch Visual Studio 2022. It will rebuild these cache files.

After this, the extension should be listed as installed, and the AWS Extension should no longer report one of the error messages listed at the top of this issue.

### Repair Visual Studio and Restart your system

* Close all running instances of Visual Studio.
* From the Windows start menu, Launch **Visual Studio Installer**.
* Run **Repair** on the affected installation(s) of Visual Studio. This will allow Visual Studio to rebuild its index of installed extensions.
* Restart Windows
* After rebooting, Visual Studio’s extension manager should list the extension as installed

### Manually uninstall the extension, then re-install it

* Close all running instances of Visual Studio.
* From the Windows start menu, **Developer Command Prompt for VS XXXX**, where XXXX is your relevant Visual Studio version.
* In the developer command prompt, uninstall the extension using the VSIX Installer by running one of these commands:
* For the VS 2022 extension: `vsixinstaller.exe /uninstall:0B82CB16-0E52-4363-9BC0-61E758689176`
* For the VS 2017 and 2019 extension: `vsixinstaller.exe /uninstall:12ed248b-6d4a-47eb-be9e-8eabea0ff119`
* Restart Windows
* After rebooting, try to install the AWS Toolkit extension again, either directly from within the Visual Studio Extension manager, or by downloading the latest version from the marketplace.

### Check the VSIX Installation Log

Visual Studio extensions are installed using a VSIX Installer. At the end of the installation, there is a link to view the installation log. This log is produced by the VSIX installer.


The VSIX installation logs are named `%temp%\dd_VSIXInstaller_XXX.log`, where `XXX` is a date/time stamp.

If you continue to see this extension missing from your Extension Manager but your installation is reporting success, check these logs for some clues. Please share this installation log by attaching it to a comment down below, or in a new issue.

## Possible Causes

* Visual Studio’s extension installer may have had difficulties properly installing the extension
* Visual Studio’s internal indexes that reference the installed extensions may have gone out of sync with the folders containing the installed extensions on your disk.
* Between version 1.53.0.0 and 1.54.0.0, the AWS Toolkit extension was renamed (from “AWS Toolkit for Visual Studio 2022” to “AWS Toolkit with Amazon Q”). This may have caused some problems with how Visual Studio manages its installed extensions.

No repository file, test, or entry point is identified. Start by reproducing the missing AWS Toolkit entry in Visual Studio's Extension Manager and review the linked Visual Studio Developer Community guidance. The documented Visual Studio 17.11.5 update and resetExtensions command are the stated resolution; no project change is specified.

Written by the indexing model from the issue text.