[CC and Milestones, error code 110-578ef827] Stuck On Loading Screen Sims 4

Do you have any LastException files in Documents\Electronic Arts\The Sims 4 ?

• Delete the ones you have
• Trigger the error again
• Check if new ones are created
• If that is the case, please copy/paste the content here. You can open the file with any text editor.

Deleting the file won't fix your issue. Posting the info is meant for troubleshooting. 

Hi, yes I did like you described, the following is the new lastexception that came up:

<?xml version="1.0" ?><root>

<report><version>2</version><sessionid>dd943a96954daa7269a73d4d</sessionid><type>desync</type><sku>ea.maxis.sims4_64.15.pc</sku><createtime>2026-03-03 16:00:51</createtime><buildsignature>Local.Unknown.Unknown.1.121.372.1020-1.300.000.234.Release</buildsignature><categoryid>developmental_milestone_tracker.py:1116</categoryid><desyncid>dd943a96954daa7269a73d4d</desyncid><systemconfig/><screenshot/><desyncdata>Exception raised while processing zone spin up sequence: 'Object not found: 0x66c0cd10' (KeyError: 'Object not found: 0x66c0cd10')&#13;&#10;Traceback (most recent call last):&#13;&#10;&#13;&#10; File "T:\InGame\Gameplay\Scripts\Core\sims4\utils.py", line 179, in wrapper&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\areaserver.py", line 222, in c_api_server_tick&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 512, in update&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\zone_spin_up_service.py", line 1881, in update&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\zone_spin_up_service.py", line 1513, in on_update&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 741, in on_hit_their_marks&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\zone.py", line 1142, in _set_zone_state&#13;&#10; File "T:\InGame\Gameplay\Scripts\Core\sims4\callback_utils.py", line 158, in __call__&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 1211, in send_all_milestones_update_to_client&#13;&#10; File "T:\InGame\Gameplay\Scripts\Server\developmental_milestones\developmental_milestone_tracker.py", line 1116, in _get_milestone_update_msg&#13;&#10;KeyError: 'Object not found: 0x66c0cd10'rtim=0&#13;&#10;Client Session Time: 25.44&#13; &#10;Num Save Errors: 0&#13; &#10;Num Load Errors: 0&#13; &#10;Current Game State: 0x96d01090&#13; &#10;LoadingScreenActiveFlag: 1&#13; &#10;Origin Version: 13,658,0,6171&#13; &#10;Modded: True&#13; &#10;SystemInfo: Windows 11 10.0.26200 GPU: NVIDIA GeForce RTX 3060 32.0.15.9186, GUID: 6306DDF4-F49C-11EF-9865-9921DD357C71&#13; &#10;</desyncdata></report>

</root>

Thanks

Hi Ghostbeeean​ 

you seem to have an issue with a milestone that was on a cc that you removed from the game.

Try this mod (it's a script mod so make sure to turn them on): https://www.patreon.com/posts/mod-milestone-81237568  (File 2: CC/Mod Object Fix).