Many people opened a thread with this error, but none of those advices worked for me.
When i opened my game today and wanted to load my family (what is also strange btw, cause before i could open my family and now i have to open a neighbourhood) the neighbourhood loaded in 1 sec and gave this error message: "A serious error has occurred while loading 'Hidden.Springs.sims3'. It is strongly recommended that you restart the application."

2 Days ago i played fine with it and i didnt change anything on the game or pc, no downloaded content, no new expansions, no changes on the pc itself.
Many say it's the security scanner that causes this error and they claime that just by 'disabling real-time in MCafee' would solve the problem.

Well, i dont even have MCafee, i had Kaspersky and it expired days ago wich was never a problem before. I never did anything with Kaspersky when i was playing the sims, NEVER ANYTHING. THE ONLY thing i did today before starting my game for the first time today was right-click on exit on the the kaspersky icon down below cause i wanted to clean the unnessecary programs there since it was expired.
But that cant be it, doesnt make sense cause now its open again and still got the error.. what is this and how can i fix it?
i just wanna know what it means and if it has anything to do with Kaspersky.. just hearing about MCafee

So you tried everything else in the Game Help:A Serious Error Has Occurred^wiki FAQ?

havent seen this before! I saw many other options but not this, will try them now.. ill turn back when i finished or when it worked..

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im trying the option wit unlocker but i have a problem. I did the first option with right click on properties and disable the 'read only' box. But after i installed the unlocker and right click on Electronic Arts Folder, the unlock option does not appear.. actually not on any folder. unlocker was correctly installed.

And also i noticed that when i gone back to properties from Electronic Arts folder, that 'read only' box is abled again, i didnt do that. When im disabling again, it ables automaticly back when opening properties... what is this?

EDIT: read that unlocker does not support windows 7 64x.. well this is great.. i didnt know what to choose when installing windows, thought 64x was a good idea..

soo i found lockhunter.. it works for 32x and 64x, but how to use on EA folder is very useful, cause clickin a wong button is no fun.

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oke, done it with lockhunter but there is no files locking in the EA folder.. now what :\
this is horrible....

Unlocker works fine on Windows 7 x64, as I'm using it. Did you install it as Admin?

And please STOP multiple-posting. The EDIT button is there to be used, don't make it feel neglected!

Oh! Goes without saying, just as an extra precaution. After you've unlocked the folders, you did close all Explorer windows, right?

installed unlocker as admin but still doesnt show up when right-click. And yes everything was closed incl. explorer windows.
Lockhunter said there are no files locking in the EA folder.. soo i guess the problem about this sims 3 error is something else than..

Is there no one who can help about the erorr?? Just deleting your family and start a new one doesnt fix anything, cause the error keeps coming for many people. We need to know why it happend in order ti fix or avoid it!

You did download the x64 bit version of Unlocker, correct?
There's an option in the Installation process to select the right-click context menu. I believe the options were selected by default. Did you disable that or something?

it was the 32 bit version, now installed the 64x version but still says theres no files in the EA folder that block, so the error must be fixed with something else.. Do u know if it has anything to do with Kaspersky? Cause it was the first time i closed the program before starting my sims.. it was expired though as i told before..

Try uninstalling it? And use CCleaner to remove all traces of it, too. Antivirus programs usually have a service running in the background to startup with Windows and is usually injecting itself right after windows stuff is loaded. So, if you simply stop the program but not its background service, the antivirus background scan is still active.
Do you have a replacement Antivirus to take its place?

Trying cleaning your disc or restart your computer i get it all the time and i do both of the things i told you & it works

just reinstalled everything and put back my old files in the EA folder inmy documents, but still the same error..any ideas??

and deleted the corrupt cc files, no succes!

Tried Diskette66 method with starting a new game in the same world en simply use its meta.data file to replace the one in the damaged world with, also no succes

I think im one of those who are not lucky with all of the options that are helpful for others.. but still i believe there MUST be something i can do.

It was way too strange and easy how this problem came, without me even doing or changing something.. so it must be undone that easy too..

That's with the same Save file as before the game reinstall? Also occurs on ALL Saves, or just that HiddenSpring Save? Does it occur for a newly created Save with the old User folders?
How about a NEW Save with NEW "factory reset" User folders? Does it get the same error at the 2nd game loading?

Kapersky already cleaned out at this point?
And Unlocker does not detect the files as still being in use or already Unlocked it and still get the same error? Windows Explorer all closed at this point? Neither restarting the game nor the system helps?
There's no other syncing/backup process running in the background like to Dropbox, Google Drive, realtime-scanning for backups and whatnot?

Disabled all background programs at this point? Just those under the username, not system name. If in doubt, Google the process name to see if it can be safely stopped!
Have you tried creating new Windows user account as a last resort?