[Bug]: 9 second Obsidian Android app startup time with Sync Engine enabled

[zzyzx-dc]

Real Outcome

I've loved using the Sync Engine plugin for several months now but lately I've had very slow startup times (5-10 seconds) in the Android mobile app. I troubleshooted the mobile app thinking it was Obsidian, but I think this plugin is the culprit.

I turned off all plugins and wiped workspace-mobile.json and achieved a 2 sec startup again. Then I turned them on one by one. No plugin increased the startup time until I fired up Sync Engine again.

Obsidian start-up time breakdown

2.6 sec without Sync Engine:

Obsidian version: 1.13.8 (367)
API version: 1.13.8
Operating system: Android 17 (Google Pixel 9)
Webview version: 153.0.0.0

- Total startup time: 2,688ms
- Initialization: 477ms
  - Boot: 342ms
    - Response: 10ms
    - DOM parse: 78ms
    - Script evaluation: 254ms
  - Language: 35ms
  - App setup: 100ms
- Vault (3,632 files): 1,082ms
  - Configuration: 51ms
  - Reading files: 1,002ms
  - Loading file metadata: 26ms
  - Metadata listeners: 3ms
- Workspace (9 tabs, 9 deferred): 129ms
  - Components: 28ms
    - Managers: 11ms
    - Settings: 17ms
  - Appearance: 6ms
  - Managers: 70ms
    - Metadata types: 19ms
    - Secret storage: 28ms
    - Hotkeys & commands: 23ms
  - Layout: 22ms
    - Load layout: 22ms
  - Extra: 3ms
- Core plugins: 332ms
- Community plugins (3 active): 668ms
  - Templater (2.25.0): 169ms
  - Book Search (0.7.5): 67ms
  - Front Matter Timestamps (1.5.5): 47ms
  - Other: 386ms

Then I turned on Sync Engine. I let it scan all files and perform a sync so everything was stable. Then I swiped obsidian out of memory and started it up again.

9 seconds with Sync Engine:

Note that Obsidian only credits Sync Engine with 249ms, but enabled Sync Engine raised the Reading files and Workspace time quite a bit.

Obsidian version: 1.13.8 (367)
API version: 1.13.8
Operating system: Android 17 (Google Pixel 9)
Webview version: 153.0.0.0

- Total startup time: 8,965ms
- Initialization: 517ms
  - Boot: 375ms
    - Response: 16ms
    - DOM parse: 72ms
    - Script evaluation: 287ms
  - Language: 37ms
  - App setup: 105ms
- Vault (3,633 files): 5,505ms
  - Configuration: 46ms
  - Reading files: 5,425ms
  - Loading file metadata: 30ms
  - Metadata listeners: 4ms
- Workspace (9 tabs, 8 deferred): 1,618ms
  - Components: 28ms
    - Managers: 11ms
    - Settings: 17ms
  - Appearance: 6ms
  - Managers: 68ms
    - Metadata types: 18ms
    - Secret storage: 43ms
    - Hotkeys & commands: 7ms
  - Layout: 1,512ms
    - Load layout: 1,509ms
    - Finalize: 2ms
  - Extra: 4ms
- Core plugins: 354ms
- Community plugins (4 active): 971ms
  - Sync Engine (3.1.6): 249ms
  - Templater (2.25.0): 160ms
  - Book Search (0.7.5): 48ms
  - Front Matter Timestamps (1.5.5): 24ms
  - Other: 490ms

Expected Outcome

Sync Engine does not slow down app load time.

Backend

Nextcloud

Steps to Reproduce

As above - enable the Sync Engine app and witness slow load time.

Logs

Sync Engine log:


Generated at: 2026-09-12 16:03:17
Plugin version: 3.1.6
Obsidian API version: 1.13.8
Operating system: Android

Trigger: manual
Started at: 2026-09-12 16:03:03
Ended at: 2026-09-12 16:03:06
Duration: 2.35 s
Outcome: noop
Logs:

INFO - Sync triggered by manual started.
INFO - Asymmetric storage ignored orphaned Adrianople red.md.
INFO - Asymmetric storage ignored orphaned Untitled.md.
INFO - Asymmetric storage ignored orphaned projects/.
INFO - Local 3703 item(s), remote 3703 item(s), record 3703 item(s).
INFO - Sync ended with result: noop.
Trigger: startup
Started at: 2026-09-12 16:02:55
Ended at: 2026-09-12 16:02:57
Duration: 1.88 s
Outcome: noop
Logs:

INFO - Sync triggered by startup started.
INFO - Asymmetric storage ignored orphaned Adrianople red.md.
INFO - Asymmetric storage ignored orphaned Untitled.md.
INFO - Asymmetric storage ignored orphaned projects/.
INFO - Local 3703 item(s), remote 3703 item(s), record 3703 item(s).
INFO - Sync ended with result: noop.
General logs:

16:02:55 - INFO - Module webdav loaded.
16:02:55 - INFO - Module smart-merge loaded.
16:02:56 - INFO - Discovered 8 module(s) from 1 source(s).

Issue Policies

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[zzyzx-dc]

I am testing further:

I disabled Asymmetric Sync, thinking that may be a possible culprit if it must cache all filenames on startup to match the asymmetric backend.

Note: disabling Asymmetric Sync and initiating the plugin's migration caused the loss of 3,700 files. I watched them get flagged for deletion. I am not sure why. Strangely, those "orphaned" files in the Sync Engine log on my original post were returned!

I have a backup, so that's fine. Maybe starting with a blank slate would be good. But that seems dangerous...

[hesprs]

initiating the plugin's migration caused the loss of 3,700 files.

This is potentially a bug. Did you see those files get wiped at remote, local, or both? What backend are you using?

And regarding the slowed startup. That's indeed very weird. Sync Engine does not interfere Obsidian startup, nor does it cache all files during initialization. Could you tell me the delay you set for the startup sync?

[zzyzx-dc]

Sure thing. Backend is Nextcloud. Startup sync was default 5 sec.

I saw them get wiped on both clients and the Nextcloud backend (I had the web UI open).

I unchecked "Asymmetric sync" (I can't recall if it was desktop or Android) and it asked if I wanted to migrate. I clicked yes and got the error message "234 items failed, status 404" which seemed strange (sync had been working and my Nextcloud instance was up). Then I noticed the files disappearing in the desktop client, and the Nextcloud UI. I was able to turn asymmetric sync off my other client. Once the dust settled, everything behaved normally, just with only a handful of notes - including, as I said, the "orphan" ones from the log, which seems strange. When I started the Android app, Sync Engine appropriately warned me about the note deletions.

This vault was not originally asymmetric. A few weeks ago I ran the migration to asymmetric. I never really noticed any errors, and didn't check the logs, so I'm not sure how long those orphan notes were on Nextcloud. Slow mobile startup time was the only reason I began troubleshooting - otherwise, syncing seemed fine. (Desktop startup time was never slow.) But I wonder if the asymmetric cache or mapping got screwed up somehow?

I still have that Vault in a backup folder on desktop. Prior to doing this, I copied the vault folder (with .obsidian plugin folders, etc). So I suppose I could run some tests again if you want. However, the Nextcloud backend has been wiped and repopulated with my notes.

---

Just FYI, my Pixel phone's OS is GrapheneOS. I'm not sure if that's relevant but Graphene handles memory and permissions a bit differently, although I use Obsidian Android with battery optimization off and compatibility mode on.

[hesprs]

Can you access your NextCloud log to see why it produced 234 404 errors? Did you have "Mirror remote" sync strategy on one of the devices?

And regarding the prolonged startup. The logs provided by you shows your configured startup delay is actually around 0s instead of 5s. Can you check the plugin settings again to confirm it literally shows "5 s" or not?

Then please set the startup sync delay to a higher value or disable it entirely and see whether your startup time goes back to normal.

[zzyzx-dc]

I had Bidirectional.

Here's my relevant Nextcloud logs: https://gist.github.com/zzyzx-dc/85badab6dc4e5bd684af49d879362aa0

Hope that link works, let me know if it doesn't!

It looks like at least one filename was too long - that's probably user error (I was using an attachment renaming plugin that began forming very long filenames).

---

Re: startup times, I reloaded a copy of the old vault, when it was taking a long time to start, and pre-deletions. It appears to have lost my Sync Engine settings for some reason. (Maybe since I copied the folder to somewhere else, it lost the keychain info?)

It warned me that I have an untested module installed, the module title said something about DAV - but now Sync Engine plugin just says "unknown module." There are two modules listed, "unknown" and WebDAV. That seems odd. In the .obsidian/plugins/sync-engine/modules, there's only webdav.js and smart-merge.js.

I would need to load this old vault on Android, and then set up a DAV backend for it, to see if startup times improved with changing the startup sync time. I am unable to do that tonight but can do that tomorrow if you need it.

Anyway - from that old vault that was having issues, here's my data.json for the plugin. Don't know if that helps.

{
  "asymmetricStorage": true,
  "confirmDeleteInAutoSync": true,
  "confirmTasksInSync": true,
  "conflictResolver": "renameAndKeepBoth",
  "customHeaders": [],
  "decider": "bidirectional",
  "exclusionRules": [
    {
      "caseSensitive": false,
      "expr": "**/.git"
    },
    {
      "caseSensitive": false,
      "expr": "**/.github"
    },
    {
      "caseSensitive": false,
      "expr": "**/.gitlab"
    },
    {
      "caseSensitive": false,
      "expr": "**/.svn"
    },
    {
      "caseSensitive": false,
      "expr": "**/node_modules"
    },
    {
      "caseSensitive": false,
      "expr": "**/.DS_Store"
    },
    {
      "caseSensitive": false,
      "expr": "**/__MACOSX"
    },
    {
      "caseSensitive": false,
      "expr": "**/desktop.ini"
    },
    {
      "caseSensitive": false,
      "expr": "**/Thumbs.db"
    },
    {
      "caseSensitive": false,
      "expr": "**/.trash"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.doc"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.docx"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.ppt"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.pptx"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.xls"
    },
    {
      "caseSensitive": false,
      "expr": "**/~$*.xlsx"
    },
    {
      "caseSensitive": false,
      "expr": ".obsidian"
    }
  ],
  "exportLogsDirectory": "Sync Engine Logs/",
  "inclusionRules": [],
  "maxFileSize": {
    "enabled": false,
    "value": 31457280
  },
  "maxMemoryConsumption": {
    "enabled": true,
    "value": 104857600
  },
  "maxRequestConcurrency": {
    "enabled": true,
    "value": 50
  },
  "minRequestInterval": {
    "enabled": false,
    "value": 0
  },
  "moduleAutoUpdate": true,
  "moduleSources": [
    "https://sync.consensia.cc/modules.json"
  ],
  "modules": {
    "smart-merge": {
      "conflictAEnd": "</mark>",
      "conflictAStart": "<mark class=\"conflict ours\">",
      "conflictBEnd": "</mark>",
      "conflictBStart": "<mark class=\"conflict theirs\">",
      "deletionEnd": "</mark>",
      "deletionStart": "<mark class=\"conflict deleted\">"
    },
    "webdav": {
      "baseDirectory": "Obsidian sync/chris/",
      "chunkedUpload": true,
      "depthInfinity": true,
      "endpoint": "https://-redacted-",
      "password": "chris",
      "username": "chris"
    }
  },
  "noticeStatusOnMobile": true,
  "realtimeSync": {
    "enabled": true,
    "value": 5000
  },
  "realtimeSyncFastMode": true,
  "remoteFs": "webdav",
  "scheduledSync": {
    "enabled": true,
    "value": 900000
  },
  "startupSync": {
    "enabled": true,
    "value": 5000
  }
}

[hesprs]

The warnings are actually expected (reason see this page). And that "Unknown Module" is the Smart Merge module exactly. You can enable both modules and they will work as before.

---

here's my data.json for the plugin. Don't know if that helps.

Yes, that's very helpful. Is the data.json your desktop settings or your mobile settings? Or you share the settings across mobile and desktop? If it is not shared, please provide the data.json on the other device.

Also, don't forget to check whether increasing startup sync delay or disable it can shorten the startup time.

[zzyzx-dc]

Interesting. I just opened one of my other clients (on a laptop) and I got the warning about an untested module but it was just webdav.js. Is the hash not matching? Once I deleted and re-enabled it, my old Nextcloud settings were present and sync works fine.

This is on a client which Sync Engine was already set up and working successfully, but hadn't been opened in a couple of days.

Unknown module

Sync Engine detected an installed module named webdav.js in its module directory. This module is neither installed in Sync Engine module management page, nor registered anywhere to be exempt from provenance validation. Please review following information before proceeding:

File name: webdav.js
File path: .obsidian/plugins/sync-engine/modules/webdav.js
Size: 20.51 KB
Created at: 2026-09-16 13:31:08
Modified at: 2026-09-16 13:31:08

Please avoid loading modules with unknown sources, as this could be a malicious attack. If you do not know where does it come from, directly deleting it is the best option. If you control the module and it is intentional, you can choose "Configure" and enable it.

[Configure] [Delete]

"Edit module information" dialog:

Edit module information

Enable — Set whether to load this module. (toggle: off)

Name — Set the name to be displayed in the module card.
WebDAV

Description — Set the description text to be displayed in the module card.
WebDAV backend support.

Icon — Set the icon to be displayed in the module card, a full list of icons can be found in Lucide Icons catalog.
server

Update — Set whether the module can receive updates. Alter the source to fetch updates from in the field; empty source means no updates.
https://sync.consensia.cc/ (truncated)

README page — Set the optional README page of the module, leaving empty means no README.
https://sync.consensia.cc/ (truncated)

Integrity verification — Verify the hash each time the module is loaded, protecting you from malicious module replacement attacks. (toggle: on)

[Cancel] [Save]

[hesprs]

If you often copy your vaults across devices or rename them, this is the expected consequence.

Please do not repeatedly report a expected behavior. Let's simply set the startup sync delay to a higher value or disable it on your mobile, and see whether the vault startup time is improved.