Home Assistant: Fix HTTP 500 update error, check disk

We recently ran into a frustrating issue when trying to update our Home Assistant setup. The update process failed with a cryptic HTTP 500 error, leaving us scratching our heads. It turns out the problem was surprisingly simple, but easy to overlook: our disk was full!

This post walks you through the exact problem we faced, how we investigated it, discovered the root cause, and the steps we took to fix it. We’ll also share tips on how to prevent this from happening to you, and what to look out for after a major update.

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What you need

• Home Assistant OS running in a Proxmox VM
• A Network Attached Storage (NAS) device for backup storage

Our Home Assistant update failed with HTTP 500

We were excited to update our Home Assistant OS from version 2026.6 to 2026.10. We started the update process as usual, expecting a smooth transition to the new features and improvements. However, instead of a successful update message, we were met with an error: HTTP 500. This is a generic server error code from a web server, meaning something went wrong on the server’s side, but it doesn’t tell you exactly what.

Our Home Assistant setup runs as a virtual machine (VM) on Proxmox. Proxmox is special software that lets us run many virtual computers, or VMs, on one physical machine. This setup usually works great, but this time, the error was puzzling.

Initial checks: System Repairs and Storage

When an update fails, the first place we usually check is Home Assistant’s built-in repair tools. We navigated to Settings > System > Repairs to see if any issues were automatically detected or suggested. There were no obvious repair items related to the update failure.

Next, we considered if disk space might be an issue. It’s a common culprit for many software problems. We went to Settings > System > Storage to check how much free space our Home Assistant VM had. To our surprise, on our 31GB disk, we only had about 1.6GB free! This was a critical clue.

The root cause: Too many local backups

With only 1.6GB of free space, it became clear why the update was failing. A Home Assistant update often needs a significant amount of temporary space to download new files, unpack them, and perform the installation. With so little space available, the process couldn’t complete, leading to the HTTP 500 error.

We dug a bit deeper to understand where all our disk space had gone. It turned out that our Home Assistant setup had accumulated 47 local backups. Each of these backups was roughly 300MB in size. These backups are important for recovery, but keeping so many locally on the same disk as the operating system can quickly consume all available space.

How we fixed the disk space issue and updated Home Assistant

Once we identified the problem, the solution was straightforward: free up disk space by moving and deleting old backups. Here’s the step-by-step process we followed:

Step 1: Copy backups to network storage

Before deleting any backups, we wanted to make sure they were safe. We copied all 47 of our Home Assistant backups to our Network Attached Storage (NAS). A NAS is a dedicated device that stores files and makes them available over a network, acting like a central file server for our home.

We carefully verified that the copied files, which are typically .tar files (a common format for archiving multiple files into one), were intact and readable on the NAS. This ensured we had a safe copy before proceeding to delete them from Home Assistant.

Step 2: Delete old local backups

With our backups safely stored on the NAS, we returned to Home Assistant to delete the oldest local copies. We decided to keep only the three most recent backups on the Home Assistant disk and delete the remaining 44 oldest ones. This freed up a significant amount of space.

Deleting the 44 oldest backups freed up approximately 14GB of disk space. This brought our free space up to a healthy level, more than enough for the update to proceed.

Step 3: Perform the Home Assistant update

With ample disk space now available, we attempted the update again. This time, the update from Home Assistant OS 2026.6 to 2026.10 proceeded without any issues. The HTTP 500 error was gone, and our Home Assistant setup was successfully updated to the latest version.

Preventing future disk space problems

To avoid running into this problem again, we took steps to automate our backup management. Home Assistant allows you to configure network storage for backups and set up retention policies.

Add NAS as network storage for backups

We added our NAS as a network storage location within Home Assistant. This means that future backups will be stored directly on the NAS, rather than consuming space on the Home Assistant VM’s disk. This is a much more robust solution for backup storage.

For more details on how to configure network storage for backups, you can refer to the official Home Assistant documentation on OS backups.

Set backup retention policy

Once the NAS was configured, we set up a retention policy for our backups. A retention policy tells Home Assistant how many backups to keep and for how long before automatically deleting the oldest ones. This ensures that we always have recent backups available, but also that old backups don’t pile up and fill our disk again.

What went wrong / gotchas

Even after a successful update, sometimes there are a few lingering issues to address. Here are a couple of things we encountered:

Custom integrations needing updates

After such a significant jump in Home Assistant versions (from 2026.6 to 2026.10), it’s common for custom integrations to need updates. Custom integrations are additional software components, often developed by the community, that extend Home Assistant’s functionality. We noticed that our oref_alert custom integration stopped working.

We checked Settings > System > Logs and saw “Setup failed” entries related to oref_alert. The fix was simple: we updated the integration via HACS. HACS, or Home Assistant Community Store, is a popular tool that makes it easy to manage and update custom integrations.

map card showing “API KEY REQUIRED”

Another small issue we noticed was with our map card, which started displaying “API KEY REQUIRED”. This was because CARTO tiles, which provide the geographical data for the map, began requiring an API key in August 2026. An API key is like a unique code or password that identifies your application when accessing a service.

Fortunately, Home Assistant version 2026.9 and newer includes a fix for this, so after our update to 2026.10, the map card automatically resolved itself once everything settled.

Pre-upgrade checklist

Based on our experience, here’s a quick checklist to consider before your next major Home Assistant OS upgrade:

• Check disk space: Always ensure you have plenty of free space on your Home Assistant disk. You can find this under Settings > System > Storage.
• Back up your system: Create a full backup of your Home Assistant setup. Store it safely on network storage if possible.
• Review custom integrations: Be prepared to update custom integrations via HACS after the upgrade.
• Check logs after upgrade: After the update, always check Settings > System > Logs for any “Setup failed” messages or other errors.

Running into an HTTP 500 error during a Home Assistant update can be alarming, but as we found, the cause can often be something as straightforward as running out of disk space. By regularly checking your storage, managing your backups effectively, and being prepared for minor post-upgrade tweaks, you can ensure your smart home stays running smoothly.

FAQ

Why did my Home Assistant update fail with HTTP 500?

In our case, an HTTP 500 error during a Home Assistant update meant the server encountered an unexpected condition that prevented it from fulfilling the request. We discovered the root cause was insufficient disk space, specifically only 1.6GB free on a 31GB disk. This was due to 47 local backups piling up, each about 300MB.

How can I prevent disk space issues with Home Assistant backups?

To prevent disk space issues, we recommend configuring your Home Assistant to store backups on network storage, like a NAS. Additionally, set up a backup retention policy. This automatically deletes older backups, ensuring they don’t accumulate and fill your disk, while still keeping enough recent copies for recovery.

What should I do after a big Home Assistant upgrade?

After a major Home Assistant upgrade, it’s wise to check Settings > System > Logs for any “Setup failed” messages, especially concerning custom integrations. You might need to update these integrations via HACS. Also, be aware that some components, like map cards, might have changed requirements (e.g., API keys), which newer Home Assistant versions often address automatically.