[Steam UGC]: Deserialization of metadata for item 3509305158 failed: While processing Steam UGC Meta

Hello Space Engineers 2 Team,

I am currently developing a larger PvE/survival mod for Space Engineers 2 called SEEM (Space Engineers Expansion Mod).

I am experiencing an issue when uploading/updating my mod on Steam Workshop. The Workshop item already exists and has previously been uploaded successfully.

Workshop item:

SEEM – Space Engineers Expansion Mod

The Workshop Item ID is:

3509305158

The previous version of the mod (0.028f) was uploaded successfully. However, after attempting to upload the newer version, SE2 reports the following errors:

2026-08-24 12:15:51.646 - Main Thread -> Error: [Steam UGC]: Steam call SteamUGC.SubscribeItem(id) failed with error k_EResultFail. 2026-08-24 12:15:51.669 - Main Thread -> Error: [Steam UGC]: Error subscribing to UGC item 3509305158: Keen.VRage.Core.Services.GameServiceException: Steam call SteamUGC.SubscribeItem(id) failed with error k_EResultFail. at Keen.VRage.Library.Threading.PromiseTask`1.HandleFaulted() at Keen.VRage.Library.Threading.TaskBase.GetResult() at Keen.VRage.Steam.UGC.SteamUGCServiceComponent.UploadUGCDataAsync(IFileSystem sourceFs, IUGCMetadata metadata, UGCBaseMetadata description) 2026-08-24 12:16:25.618 - VRageWorker 0 -> [Steam UGC]: Deserialization of metadata for item 3509305158 failed: While processing Steam UGC Metadata:28:24: Expected end of string, but instead reached end of data. LineNumber: 27 | BytePositionInLine: 4218.. 2026-08-24 12:16:25.619 - VRageWorker 0 -> Warning: [Steam UGC]: Failed to parse metadata for item 3509305158. Skipping.

The most important part appears to be:

Deserialization of metadata for item 3509305158 failed Expected end of string, but instead reached end of data LineNumber: 27 BytePositionInLine: 4218

From the error, it appears that SE2 is attempting to deserialize Workshop metadata and encounters an incomplete/invalid string.

I would like to clarify whether this is:

1. A problem with the Workshop item's existing metadata,
2. A problem with the SE2 Workshop uploader generating the metadata,
3. A problem with my mod/project metadata,
4. Or a Steam UGC issue.

The previous version 0.028f of the same Workshop item was working correctly, so I am currently considering rolling the Workshop item back to that version to see if it restores normal functionality.

Before doing anything that could potentially make the Workshop item unrecoverable, I would appreciate your advice.

Additional information

• Game: Space Engineers 2
• Mod: SEEM – Space Engineers Expansion Mod
• Workshop ID: 3509305158
• Previous working version: 0.028f
• Problem occurs when updating/uploading the existing Workshop item
• Error appears to involve Steam UGC metadata deserialization
• LineNumber: 27
• BytePositionInLine: 4218

Could you please advise whether this error is a known SE2 Workshop/uploader issue and whether there is a recommended procedure for recovering/updating the existing Workshop item?

I can provide the complete log, project files, metadata files, or any other information needed for investigation.

Thank you for your help.

Best regards,

AngryWolf

SEEM – Space Engineers Expansion Mod

Additional screenshots :

My actual metadata file in local project inside editor :

Error while selecting a project on the HUB list :

When i try to upload a mod to steam :