So, it's been a while since I ran
sfdx update and the update was larger than average (138 MB). After updating the CLI failed for 2 days straight, it finally worked for me this morning.
The next step that
sfdx update runs is updating the plugins. Even without having any plugins installed other than the ones that come standard with sfdx, it appears that those too had a significant amount of data to download.
I've been getting the following error
error An unexpected error occurred: "https://registry.yarnpkg.com/rxjs/-/rxjs-6.6.7.tgz: ESOCKETTIMEDOUT".
sfdx-cli: Updating plugins... !
» Error: yarn add @salesforce/plugin-user@latest --non-interactive
» --preferred-cache-folder=C:\Users\[redacted]\AppData\Local\sfdx\yarn --check-files exited with code 1
Before I received that error, the cli told me "there is an issue with your network. Retrying".
How do I fix this?