Hash sum mismatch error while upgrading

I'm using Pop_Os! 20.04. While trying to upgrade it i'm getting the following error :

sudo apt-get upgrade

Get:1 focal-updates/main amd64 apparmor amd64
2.13.3-7ubuntu5.1 [494 kB]
Err:1 focal-updates/main amd64 apparmor amd64 2.13.3-7ubuntu5.1 Hash Sum mismatch Hashes of expected file: - SHA256:6359c1166bdc8946d83d5ccf0a51d22d3e65698bcbfb407b8c51cb0cf0fa693b - SHA1:583e8718e1d7df0ac1cec1d172a00b5c1f3e068a [weak] - MD5Sum:c9472e4b9fed70d333a94abf4def982f [weak] - Filesize:494020 [weak] Hashes of received file: - SHA256:3e93ae0f10e6ad2f187e62d903692ea4d1df89aabbf0bc0b891f0ccb1a7a1f06 - SHA1:2b2318c322cf63cf31a9a956b8e1fc4109c95071 [weak] - MD5Sum:16db382d293cd562a529fbcc52b69691 [weak] - Filesize:494020 [weak] Last modification reported: Fri, 22 May 2020 11:58:22 +0000
Fetched 494 kB in 1s (636 kB/s)
E: Failed to fetch Hash Sum mismatch Hashes of expected file: - SHA256:6359c1166bdc8946d83d5ccf0a51d22d3e65698bcbfb407b8c51cb0cf0fa693b - SHA1:583e8718e1d7df0ac1cec1d172a00b5c1f3e068a [weak] - MD5Sum:c9472e4b9fed70d333a94abf4def982f [weak] - Filesize:494020 [weak] Hashes of received file: - SHA256:3e93ae0f10e6ad2f187e62d903692ea4d1df89aabbf0bc0b891f0ccb1a7a1f06 - SHA1:2b2318c322cf63cf31a9a956b8e1fc4109c95071 [weak] - MD5Sum:16db382d293cd562a529fbcc52b69691 [weak] - Filesize:494020 [weak] Last modification reported: Fri, 22 May 2020 11:58:22 +0000

I have looked at different solutions which try to fix it when this occurs during

sudo apt-get update

but my update command works fine.

Solutions i tried were removing the apt lists and updating it again. I also tried setting acquire-by-hash to yes but it didn't work either. I think the problem here is not the same.

2 Answers

The following steps might help solving the issue:

Refreshing the APT cache

sudo apt-get clean
sudo apt-get update

Refreshing the APT lists

sudo rm -R /var/lib/apt/lists/*
sudo apt-get update

Refreshing both

sudo apt-get clean
sudo rm -R /var/lib/apt/lists/*
sudo apt-get update

But in cases it might be simply a temporary issue with the used APT mirror, which means that you should take a coffee and retry a few hours or a night later, before investing too much time to investigate an issue which solves itself shortly after ;).

(Running Mint in a VM) - I had to disable the Windows Sandbox feature AND WSL. Then I could just run the sudo apt update command and everything was fine.