"exception while signaling: The Parent property of StarterPlayer is locked" —happens on every new place, only under one Windows user account

Bug Reports Studio Bugs
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Every time I start Play Solo (or the character otherwise tries to spawn) in a brand new, completely empty place, I get this in Output:

exception while signaling: The Parent property of StarterPlayer is locked

The character never spawns and the camera stays fixed. This happens with zero scripts in the place — I’ve deleted everything under StarterPlayer and Players and the error still fires.

Log excerpt (from %LOCALAPPDATA%\Roblox\logs, timestamps trimmed for readability):

[telemetryLog] State: PlaySoloEnterDataModelScopeServer
[telemetryLog] TaskNames: AssetDataModelPluginLoaderWaiting - Server data model ready;PlaySoloEnterDataModelScopeServer;
[FLog::Error] Slot Exception
Error: exception while signaling: The Parent property of StarterPlayer is locked
[DFLog::StudioPerformanceMeasurementsSummary] StudioPerformanceMeasurements summary for StudioStartPlaySolo: 159ms

Earlier in the same session log, I also see:
[FLog::StudioTestService] Setting up StudioTestService
right before the error fires, which is what led me to suspect StudioTestService / an automated-playtest hook is involved.

Session identifiers (from log, for support to correlate):
osversion: 148.10.0.26200 (Windows)
studioSid: 354D71A5-5D6B-41FF-807C-8B8F94AD7E86
clientId: E5A3228C-2C70-47A2-A9FE-42606302170F

Scope / reproduction pattern

  • Happens only in newly created places. Places created before this started still open and play fine.
  • Happens only under one specific Windows user account on my PC. Creating a brand-new Windows user account on the same machine, same Roblox account, fixes it completely.
  • A friend opening the same (affected) place on their own PC has no issue.
  • Publishing the place to Roblox and playing it live (in-client, not Studio) works fine.

What I’ve already tried (no effect on the affected Windows account)

  • Reinstalled Roblox Studio completely
  • Deleted/renamed %LOCALAPPDATA%\Roblox and %APPDATA%\Roblox
  • Deleted the HKEY_CURRENT_USER\SOFTWARE\ROBLOX Corporation registry key
  • Removed all Studio plugins
  • Removed a third-party AI coding tool (Ropilot) and its background process/plugin
  • Checked Task Scheduler — no leftover Roblox/Rojo/Argon/Ropilot tasks
  • Cleared all Roblox-related entries in Windows Credential Manager (RobloxStudioAuth tokens, cookies, oauth2 refresh token)
  • Checked roblox.com Settings → App permissions — only “Roblox Developers Conference” is authorized, nothing else
  • Tried a different Roblox account on the same (affected) Windows profile — still broken, so this is not tied to my Roblox account/its settings at all
  • Fresh Windows user profile on the same PC + same Roblox account = works perfectly

One more detail on what gets deleted
When this happens, the auto-generated default scripts under StarterPlayer (e.g. the default StarterCharacterScripts contents) get wiped. However, when I manually added my own LocalScript directly under StarterPlayer, that one was not deleted — only the default/auto-created instances disappear. This might narrow down which part of the engine is trying (and failing) to re-parent things under StarterPlayer.

Given that literally every client-side/account-side thing I can control has been reset and the issue persists only on this one OS user account, this looks like it might be tied server-side to something keyed off clientId/studioSid, or a corrupted per-install state that isn’t stored in AppData/Registry/Credential Manager. Happy to provide the full log files if useful.

Expected behavior
Play Solo should start normally and the character should spawn, as it does on every other account/profile.

22 Likes
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Did anyone had an issue with that before? I faced it only now, I think that might be just a roblox’s issue since i never had it before, i noticed that when this bug occurs, there’s no “FeModule” in your player’s scripts which might be just a failed update or changes related to that module.
If im not wrong, they wanted to make it’s API closed, maybe they thought locking starterplayer’s parent or starterplayer as an instance would solve it.
Edited: Ima try rq, try to insert FeModule myself and then check if that solves anything
Edited (2): Okay, now I am pretty sure that roblox’s staff is making changes related to the as called PlayerModule (before it was called femodule).
IF you don’t know what PlayerModule is, basically that’s a part of roblox core scripts which responses for player’s camera and player’s movement, the reason it DOESN’T WORK FOR NOW is because Roblox is adding new changes to it.
If you want to test your game, or check on it by using Roblox’s test function and being unavailable to do it because of the changing process or unfinished changes related to the PlayerModule by Roblox, you either be patient and wait until Roblox solves this problem or you can copy & paste PlayerModule then write script that launches it per joining and be free to test your game on your own.
Roblox-Client-Tracker/scripts/PlayerScripts/StarterPlayerScripts/PlayerModule.module at roblox · MaximumADHD/Roblox-Client-Tracker · GitHub
(^ This one is most accurate one i found, just copy & paste PlayerModule and then copy & paste rblxcharactersounds with “AtomicBinding” named module in it)
Don’t forget to launch them by using LocalScript, just copy & paste these modules, then use local script to launch them.

require(script.Parent:WaitForChild("PlayerModule"))

require(script.Parent:WaitForChild("RbxCharacterSounds")

P.S: I hope I solved your case, the reason camera stays fixed and error occurs is because Roblox is doing changes to the PlayerModule’s API so it got locked for a while, only option to fix for now is copy & pasting opensource PlayerModule’s API (They’re same dw)

6 Likes
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Thank you for reporting this issue. Could you upload the full log for us to review? Can use the following steps:

  1. Exit Studio normally, do not force quit
  2. Grab the most recently created log file using the instructions here. The file should look like 0.732.0...Studio_A1B2C_last.log
  3. Send the logs to the bug-files group, copy the link to that private DM, and post it back to this thread, following the instructions here. That copied link is only accessible to Roblox employees. Do not upload the files to this thread.

Also, does the user account on Windows experiencing this issue happen to have non-latin characters in the name? Don’t share the username here, if you’re not sure you can share it in the bug-files thread mentioned above. This issue looks very similar to another issue we’ve been investigating that has this “The Parent property of StarterPlayer is locked” log.

4 Likes
4

It says while trying to post: Private content must not be more than 10000 characters. What should I do? Should I somehow split it? My file text has exactly 783.661 characters. It’s 78,3 times bigger than the limit.

5

Are you able to attach the log as a file instead of copying its contents into the message?

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Oh, I forgot about that, thanks! Just wait a minute and I will share the link.

1 Like
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https://devforum.roblox.com/t/private-information-bug-report-from-easygamesqq/4777584

8

Have you received the file from link that I sent?

9

Yup, got it! We’ll take a look through

1 Like
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Thank you so much! :heart: By the way, good luck making sense of that massive unformatted wall of text—I honestly don’t know how you guys read through all of that!

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Btw, I also wanted to apply for Software Engineer at Roblox HQ, but when I first learn C++! :grinning_face:

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Have you received the file? Thank you for helping! And sorry for the late answer. I was on a travel.

2 Likes
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Yes, we’ve received it, thank you!

We are actively looking into this issue. It may take some time for the fix to release, we appreciate your patience while we work on this.

4 Likes
15

Hey, what’s up with this issue? I’m having it too and its quite annoying to have to go inside the real game just to test each time.

3 Likes
16

By the way, you can use team test instead of going into real game each time. Well at least it is working for me

1 Like
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Can you please fix that error in Studio, Roblox Staff, My team and I are trying to test our newest game and we couldn’t run the game, but It’s very important and team test is not working too for us. We don’t want to publish game and then test it.

18

Should I reinstall Roblox Studio?

1 Like