Hey MTS!

So, as you read the title, I have a problem about loading the game (The Sims 2 Ultimate Collection - ver. 1.17.0.66)
Let me be clear: the game runs pretty well (sometimes I get mysterious crashes, but I know that the game code is crap, it's old and etc.) but when I open it, it takes so much time to just show the window to me.
I explain: when I press Play in Origin to open it, the game just hangs for some minutes (usually 3 up to 5 minutes) and then it starts normally.
I checked in the Task Manager to see what's happening and I saw that the game loads into memory slowly.
In fact the Memory value of The Sims 2 process in Task Manager slowly starts from 60/70 MBs and after reaching 350/360 MBs it magically starts.

I checked my HDD and it's ok, I removed all the CCs, I reinstalled the game but nothing fix it.
You could say: "be patient" but trust me, it's so annoying, specially when the game crashes.
One thing I noted is that this problem appeared after a Windows 10 update long time ago.

Oh and, these are my specs:
CPU: Intel i5-4440 - 3.10 GHz 4C/4T
GPU: Sapphire Nitro+ Radeon RX 480 (AMD)
RAM: 16GB DDR3 @ 1866MHz
OS: Windows 10 May 2019 Update (but I installed the game a couple of years ago or more)

I hope you can help me.
:-)

A few seconds to around 5 minutes of "nothing happens" loading before the actual loading screen pops up isn't uncommon (can also be an issue with Bodyshop).

I sometimes get this for up to maybe 2 minutes with the game, and for Bodyshop it depends how much CC I have - the more, the longer the "nothing happens" loading is going to be.

Things like the 4GB fix and the memory allocation fix may be of help - see this video: http://www.modthesims.info/showthread.php?t=610641 - particularly if you also have random crashes.

One of the Win10 updates created a lot of issues for 32-bit games like TS2, and as far as I know this hasn't been fixed yet, so I wouldn't be surprised if that's the issue. I had extreme pink-flashing and crashing issues at first on my Win10 laptop.

how much CC do you have? It all needs to be processed during loading the program and this can take some time (especially if there're some conflicts).
Overbloated caches (though in S2 it's never that bad as in S3) may add to this, too. Some errors in Bodyshop (as @simmer22 wrote) may be a source of problems but if there're some problems you will soon meet them ingame.
And there's a question of the state of the machine - HDD fragmentation (minor problem for SSD, but files on SSDs may be fragmented too).
Origin itself adds (even "offline") some taxing (also during the loading) but until the machine is in a bad shape, or very weak it's rarely even noticed.
Antiviruses tends to get in the way, especially theirs pointless now "behavioral & preemptive alorithms"). Disconnect and disable.
Win 10... oh well. This is the case "anything bad is possible".

Start diagnosis in the order I've write.

Already done everything you said.
In CrystalDisk Info the HDD is in GOOD state, I don't think it's a hardware problem.
Also if I need to say, CPU runs just fine, I clean my PC every 4/6 months and once a year I change the thermal paste.

I don't have any AV installed, just Windows Defender (also sometimes disabled).
I tested the RAM with MemTest86 and they're fine.
Cleaned game caches, CCs, neighborhood files and etc., still nothing.

I'm now trying the 4GB patch and Memory allocation fix.
I hope the problem is the GPU driver and not Windows itself... but I'm skeptical.

For me, the additional waiting time used to be quite common with Bodyshop (didn't load until the loading screen started moving, but loaded much faster the second time within a power on/off cycle), but with my game it has been more an occasional problem. This is for my old laptop (Win7) and stationary (Vista), both with single-CD versions of the game. I haven't done a lot of testing yet with my new laptop (Win10, UC and Origin). I've usually cleared cache files (not thumbnails) every time I've played, or the game and Bodyshop tend to refuse to load. Age/status of the machine hasn't seemed to matter much, as the older ones ran the game fine for several years (between 6.5 and 8.5 years before they started having some hardware issues). I've occasionally had similar issues with other programs, so it's not certain this is just Sims-related.

It does not need to mean there is something wrong with your machine or hardware. This does seem to be more of a memory loading issue or perhaps a program loading issue of some sort, because during the "silent loading" the program does show in the task manager and seems to be working in the background. A lot of CC could be an issue, but considering I've had this issue only randomly appear on the same computer(s) with roughly the same amount of CC each time, there may be a background issue. For me it's mostly been a Bodyshop issue (which does seem to spend longer time silently loading if you have a lot of CC).

I've had occasional slowdowns and weirdness caused by antivirus programs (Norton in particular - it wrecked havoc on my ingame camera a long time ago), but this of course depends on the AV program you're using. Some cause weird issues in the game (like the spinning TAB camera I had), some will constantly try to quarantine sims files, while others play nice with the game but may cause slowdowns when you do full scans. Some you hardly even notice.

Yeah, It's a memory loading issue... the process is pretty much "alive" in the background.
Unfortunately, I think I need to wait everytime at least 5 minutes... I still used the guides that you kindly provided. Thank you
At least I hope the game crashes less!

Windows Defender is... probably not the best protection. The Win10 version is supposed to be better than the previous versions, but I'm not sure I'd trust it entirely.

Spyware and various other harmful malware have an easy way into your computer via internet if you're not careful, and they can even be the cause of slowdowns to your system (bitcoin miners are popular types of malware these days, for instance - and they can cause system slowdowns).

Do you have problems with other programs being slow? If so, you may want to do some general computer maintenance. At the very least do a basic desk cleanup to remove Temp files and such, and do a malware scan. Turning off programs that don't need to run at startup may be a good idea, since it frees up memory and processing power.

If you have (or later get) a SSD, don't use the defragmentation program on it. It's meant for regular HDDs, and the process can potentially shorten the lifetime of the SSD.

Running the game through Origin could potentially (not sure) be an issue if your internet connection is slow.

I have this same issue, I think. DVD version of the game. Windows 10 64-bit. Very little custom content to speak of. I click the desktop icon for the game, wait a bit, launcher pops up, I click play. The resolution switches to the in-game resolution and then stays on the desktop and "seems" to do nothing while the game loads into memory. In fact, Task Manager claims that it's not responding. The game takes almost exactly 4 minutes to start every time. The game files are on drive D, an HDD. The neighborhoods, downloads, etc. are on drive C, an SSD. So anyway, the game launches and acts perfectly normal after all that. Loading screens are actually pretty quick. I did the 4 GB RAM patch as well as the graphics rules fix, but launching is still lengthy endeavor. I've been trying to figure out the cause, but I believe it's just a Windows 10 thing.

It had always loaded perfectly fine on my Windows XP and Vista computers, and even my Windows 7 laptop. I suppose it could be a 32/64-bit issue. Windows 10 is the only 64-bit OS I've ever had.

I don't have that problem and am using Windows 10 - my game loads rather quickly (I do have around 7GB of cc).

Bodyshop does take long, I believe that is normal.

My advice would be to turn off unnecessary apps in the background/ start up.

Re the Windows 10 antivirus: if you had any pro antivirus (I had Kaspersky) before Windows 10, you get the pro Windows antivirus (formerly known as Essentials or something) - so that is what I have and it has given me absolutely NO problems at all.

I have been doing this since Win 10 came out Using the UC.