"An error occurred while synchronizing metadata." on VS Code MacOS 26 Aarch64

[bencer3283]

Just upgraded to the latest version of STM32Cube for VS Code extension (3.6.4) and now the extension stopped to work. I've tried reinstalling the extension pack several times. Every time after the bundle was installed an error show up saying "An error occurred while synchronizing metadata. Please try run "STM32Cube: Install prerequisite bundle" and "STM32Cube: Synchronize pack list". Or work offline."
Running "STM32Cube: Install prerequisite bundle" from the VS Code command palette will result in a message saying "No STM32Cube bundle to install", subsequently running "STM32Cube: Synchronize pack list" will return the original metadata synchronization error.

I checked my HOME/Library/"Application Support"/stmcube/ directory, the bundle/ folder seems to contain what I expected, things like cmake, gnu-gdb-for-stm32 or the stink-gdbserver, etc. However, the packs/ folder is empty, not sure if that's the problem. 

I checked the output log of STM32Cube Core and found the following:

```

[Info] 'cube pack sync' exited with signal null [1]

[Error] Failed to synchronize PDSC metadata: Syncing metadata information /Users/poshengcheng/Library/Application Support/stm32cube/packs

Snapshot is already up to date

Syncing online metadata information /Users/poshengcheng/Library/Application Support/stm32cube/packs

Checking pidx https://developer.st.com/st-pack-server/api/v1/pidx/STMicroelectronics.pidx... (1/1)

Error during metadata sync: Error: Unexpected close tag

Line: 4

Column: 117

Char: >

```

Additionally, after I selected a MCU device in "Setup STM32Cube Project(s)", downloading the supporting packs for the specified device always fails. The following message is from the output log of STM32Cube CMake Build:
```

2025-10-17 22:58:45.028 [Info] Pack STMicroelectronics.stm32l4xx_dfp.1.1.0 (1/1)

2025-10-17 22:58:45.028 [Info] Downloading https://developer.st.com/st-pack-server/api/v1/pack/STMicroelectronics.stm32l4xx_dfp.1.1.0.pack... (1/1)

2025-10-17 22:58:48.060 [Info] Unable to install pack STMicroelectronics.stm32l4xx_dfp.1.1.0

2025-10-17 22:58:48.061 [Info] Error during installation: Error: Could not fetch content of pack-URL: https://developer.st.com/st-pack-server/api/v1/pack/STMicroelectronics.stm32l4xx_dfp.1.1.0.pack, got: 503 - Service Unavailable

2025-10-17 22:58:48.069 [Info] 'cube pack install STMicroelectronics.stm32l4xx_dfp.1.1.0' exited with signal null [1]

2025-10-17 22:58:48.071 [Error] Failed to download pack 'STMicroelectronics.stm32l4xx_dfp.1.1.0'. Please check your setup and try again (via command line 'cube pack install <pack_id>' or via command palette 'STM32Cube: Restore STM32Cube CMake projects configuration')

```

So far I've only been able to build the project but attempts to debug have failed since the stm32cube doesn't seem to be able to setup the project with the selected device. 

[WH485]

I'm the same; many chips can't be selected—they can be compiled but not flashed.

[JSchn.4]

Same issue here, had to go back to old version.

[bencer3283]

For some reason if the device pack failed to be downloaded you won't be able to select that family again - if you delete the HOME/Library/"Application Support"/stmcube/ folder and run "STM32Cube: Install prerequisite bundle" again you might be able to select every device again.

But for me, downloading the device pack still fails every time.

[LNR]

Same issue on VS Code Windows as well. It's happening to both my computers.

[Marrido]

I also encountered the same problem on WINDOWS, and now I am completely unable to use it

[SGide.1]

Can confirm its affecting me as well on Linux.
Seems like the pack api server is down/broken. Hopefully ST can fix it this weekend.
I can build projects but not debug with the stlink gdb server. Went back to using cortex-debug and that is working OK for now.

[nn11]

Has there been a solution found?

[maxcarlo]

I’m facing a similar issue after updating to 3.6.4 — it seems like the pack synchronization is failing due to a metadata parsing error (Unexpected close tag) on the ST pack server. The 503 response also suggests a temporary server-side issue. You could try clearing the .stmcube/packs folder and re-syncing once the ST server stabilizes. Running cube --pack-update from the CLI sometimes helps too. Hopefully ST resolves this soon, as the new version seems to break metadata sync on macOS (Aarch64).

[ecorm]

To the STM32 team, may I suggest that you don't publish updates on a Friday if you're not going to be around during the weekend to fix issues like this?