Okay here is what happened, I'm here because I would like to understand what really happened:

I was creating new neighborhood, added downtown to it, went on to decorate downtown with some lots that I had just downloaded. I also downloaded a camera mod from MTS2 because I wanted to see edges of area. I had also downloaded ACR but that shouldn't matter because I didn't go live mode at any lot, but I'm mentioning it just in case. Neighborhood had zero sims and it was unplayed and freshly created.
First everything went well, I gone lots, made minor changes here and there. Then I added Starbucks the Bridge http://www.modthesims.info/download.php?t=463109 to my neighborhood middle of Maxis downtown buildings and tried to load to the lot. Suddenly whole my PC crashes. I mean, what the...!? I have 8GB memory and pretty good hardware and I play table PC that doesn't tend to heat up even when I play more speedy games, so I'm absolutely confused. My graphics card is also only some months old so I do not think it has let me down yet. So I did some testing:

I went on and tried to add Starbucks to another neighborhood (freshly created too, just for seeing what happens) and same repeated. PC booted again. Then I tried to add some bigger lots with lot of layers and furniture to exact same place in even more testing neighborhoods, but I was able to load them without problems and there was nothing unusual. Then I went back to the neighborhoods where I had placed Starbucks and even the surrounding lots either crashed my PC or didn't load. While same lots worked perfectly smooth with 20 something seconds loading time in neighborhoods without Starbucks.
Confused and worried I kept testing in my first neighborhood. I removed Starbucks and tried to replace it with something else. But the new lot crashed too even Starbucks was no longer in the neighborhood. I also tried to visit surrounding lots, but they also crashed, even after Starbucks was gone. I figured out there was something wrong with neighborhood, so I went back to my testing ones (which were identical to my first one except that there had not been Starbucks). I added more custom buildings around, everything still kept working. Until I discovered also 16 The Bridge from same creator did exactly same as Starbucks. But no other lot showed any problems except after 16 The Bridge had been around, just like lots surrounding Starbucks in my 1st and 2nd neighborhood did.

Could somebody explain what is going on here? Is my PC dying, has my game got borked or is it possible this issue is connected to something that came with Starbucks itself? And if yes, is the lot corrupted or could this be custom content related problem?

Well, first of all I would delete your cache files. That might explain the crashing after you removed the custom lot (might).

Secondly, when you installed and loaded the lot, did you also have all the required custom content in your Downloads folder? I ask because very occasionally complex custom lots (and that's a fairly complex lot) will not load without particular items of CC.

I shouldn't think it's your computer unless you've been very unlucky.

My guess is it's a piece of custom content in the lot rather than the lot itself. Most times it will be something innocuous as a kitchen counter.

I'd say the most likely possibility is the lot itself or something in it causing the problems.

Are you sure it's not the camera mod messing up? Which one did you install?

If you don't have M&G you might have troubles with lots that require it, even if you install with the Clean Installer. AL/M&G are a bit finnicky there. M&G is sort of considered an EP, so if any M&G items are present, that might be the cause.

To figure out if it's a CC item, try a 50/50 with the CC that came with the lots you downloaded. I've had a couple of seemingly innocent-looking object that crashed in buy mode, crashed lots, and crashed 'hoods, so I know how much trouble they can cause.

Well, the lot contains this item:
Medium Shrubby Shrub by HystericalParoxysm
which was one of the items that gave trouble in Polgannon if you remember that.

Thanks alot for all the answers!

I installed it because there was nowhere mentioned I need any more CC, and I used Clean Installer. But lot of lots are packed without certain pieces of CC (accident or old file I don't know) and no matter how many times I'm checking the post I can't find any more requirements for the download.

I'm not sure if camera is guilty, it's Tom D's camera from MTS2 (unfortunately I didn't back up my cameras because I assumed there is standard camera available somewhere if it really causes problems which I didn't expect). And I got M&G and full set of EP's, sorry for not mentioning it. I didn't intentionally leave any CC out though, but it came to me as surprise it really can cause this much trouble... Shrubby Shrubs I apparently had but it was worthy tip

Do you think writing down Clean Installers list and trying to find and download each item individually could solve problem?

The camera should not be a problem - have used it for a very long time now.
I know that the shrubby shrub gave me some problems too - I have a list of stuff in a DO NOT DOWNLOAD AGAIN document on my pc, and the shrubby shrub is on it, but I cannot remember why.

I think I'd like to see that list JP.

When I built Polgannon, I wanted more plants in order to give the village a more 'natural' look to the gardens and those shrubs are ideal in many ways (especially with Gwenke's variants). They are EAxis-match obviously and so fit with the rest and then you get a variety of shrub sizes. If I build another one though, I'm going to have to think about including that stuff again. It works if you have all the required files in your Downloads folder but not everyone wants to download CC and it would be better if lots didn't crash because that stuff is missing and the game was able to do what it's supposed to do in that situation (substitute the original item the object was cloned from). I had a look at the files with Polgannon but I couldn't see anything obviously wrong. I'm not an expert mesher anyway and HP is/was far more handy with that stuff than I am.

So you think that the Shrub itself might as separate download be potentially causing problems?

No - I think the problem arises if it's not in your Download folder. You might need the other items from the set to go with it.

It is, I checked it over after your message (thank you a lot for tip). I wrote to JP because he/she mentioned it was in their list of downloads to never download again.

Edit: sorry I hadn't seen your message after it where you told you had took a look at the shrub (missed it probably because i was writing at the time).

I *think* the issue might be because they are slaves. One of the reasons why I don't like slave sets. Though in this case, they are slaves of EAxis objects. The only thing I can think of is HP made a mistake when she made them (the same issue is present in the Gwenke variants but they are clones of HP's shrubs).

One more thing coming to my mind is that since I have used lot of subfolders and downloaded several houses at once (and some of them had their CC in separate folder which I just pasted to downloads folder as subfolder) there could be issue about duplicate files for some items. I don't know what game or my PC would do in that case.

Edit: forgot I had also downloaded and installed CEP short ago but I saw no problems in that little I had time to play between. On the other hand I haven't used any custom content on lots I played after installing CEP and before installing buildings, because items I needed CEP for were modern and lots I played after installing it were not (that's actually why I then downloaded the buildings this trouble started from). I also run 64-bit, don't think that has to do with anything but mentioning it because it's really strange my PC actually boots and doesn't just crash the game.

Edit 2 (yes I make lot of edits...): I downloaded Delphy's download manager to help me remove duplicates. It seems to list shrubs as duplicates but that's probably because they are special (can't find two of them and I got list in alphabetical order).

@maxon - it was a long time ago and it is probably possible that I downloaded just slaves and not the master (could have been with a lot too, I cannot really remember.). Yet those shrubs are present in a number of downloadable lots, so they do work for some players. However, I have certainly concluded that certain cc items simply do not work properly in my game and others work like a charm. I think I have heard that a cc item could simply not work in one game depending on the pc/system/whatever it was created on in the first place.
Strangely enough, I have no problems with the Gwenke varieties! But Gwenke's have new GUID's, which is different from HP's (I've just checked) - so maybe that is simply something to with that.
I would say, though, @Acadia, it is probably worth doing a check with the Clean Installer after pasting new cc in your downloads folder before playing.
I have learned that it is also worth reading every word a creator has written before downloading anything

Also I don't think you understood what I meant by a piece of cc causing issues. I grabbed a lot of a well known creator and it crashed, turned out it was the kitchen counter that came with the lot, I downloaded it again with the same result. Other times I piece of cc can become corrupted, maybe because you have moved it too many times or if came over badly when you downloaded, a form of computer hiccup. No ones fault and it can happen to anything. I had an elder male outfit for years which suddenly started crashing my game, it happens.

Yes reading instructions is very important but while trying to solve this issue I have gone back to where I downloaded each item and even read comments sections (except for CEP I only checked few first comments because it was simply too long to be read in one day). I found nothing. I even gone as far as tracking some individual downloads included in lots and reading their instructions. As for the Clean installer, I apparently don't know how to use it proper because I don't understand how it's going to help me anything more than providing list of custom content that lot is shipped with.

@Acadia - I meant just run it to check if you have doubles in your downloads as well. It will show up your duplicates - they will be highlighted pink, and you can remove them.
Jo is right, I also had a kitchen counter once - it happens.

What I would do is remove all the recent cc that you got and see if your game still crashes. If not you either have to work out what is causing it or just toss the lot.

If I remove recent CC that means removing CC that belongs to the lot, unfortunately. And so far my game (and PC) only crashes on these custom lots by Itas84 (haven't visited other lots long so hard to be sure). Don't you think removing CC that belongs to lot/remaining lots would only make problem worse? Luckily I should be able to take copies of my neighborhood and test which lots are okay one by one, then maybe attempt to fix the rest if I still got energy... I definitely don't dare to play my favourite sims before this trouble is over though.

What becomes to removing recent CC completely in order to avoid problems with game in future, I don't even know how to do that because Clean Installer installed it all for me (so it would be pretty hard looking for it and I mostly have no idea what all came with those lots).

Can btw having duplicates really cause problems or is that something I shouldn't waste energy thinking? I'm just wondering because it looks like things got worse after I tried to clean up in my downloads.

If you have a piece of corrupted cc in that lot, it will always crash. If you place the cc in other lots they will also crash. What you do is make a back up first and place that in a safe place and then go in and test. So say you have 20 new items, you test the game with just those 20 and the lot will crash if it's a piece of new bad cc. You then halve it and test one half and then test the other half. Hopefully one side will be fine and the other half will crash, so you put aside the good half and now you only have 10 files to test, so you half and test until you find the bad file. People having been doing 50/50 searches for bad cc ever since cc was made, I've done 3 or 4 with over 10,000 files. Once you have the culprit simply remove it and restore to the backup. You can also do it in a test hood.

Problem here is I was rushy and installed several lots at once so tracking down which CC came with those lots is pretty difficult, especially because I already had lot of CC previously...

Also are you suggesting I place items that came with lots to other lots and try to locate when the game will crash? Or what is the idea... I got confused. Or that I remove half of CC items and then load one of problem lots? Isn't it guaranteed lot will crash if half of CC is missing at that point?

No I was saying most people once they have a piece of cc, use it around their game. For example you download a mirror, you don't just use it in one lot, you might use it in a dozen lots. If that mirror is corrupted you are in trouble. So if you don't locate and get rid of that cc you are keeping trouble.

Have you never done a 50/50 search before? if so you are very lucky! This is one of the major reasons people will say it pays to keep cc organized. With new lots I put the cc in a folder called the name of the lot now. Did you put the cc into folders? If it's all tipped into your download folder you will have to do the half/half test on the lot like i have done. basically it's an all day job with plenty of chocolate and a good book if you have a decent amount of custom content.

One way to find the cc is to package up the crashing lot and look at it in Clean Installer. In there it should show you all of the cc used. Sometimes all the cc doesn't come with a lot but hopefully all your cc will. Then with CI locate and remove the cc.

I have downloaded the lot again and looked the package in Clean Installer and I have list of content but the content is right where Clean Installer put it, which is among my 17000 downloads, and lets say I don't use subfolders that much. And we don't talk about one crashing lot (many of that creators are doing it). Oh right, this is going to be a long day... And I will also need notebook and pens so I know inside game which items I need to test. Sad. Everybody was too nice to say it to me straight but I know I shouldn't have downloaded so many things at once. If I only had given myself time to play with CEP and new camera before I proceeded installing lots, and if I had not installed all of them together, this wouldn't be half as painful. That being said, excuses to eat lot of chocolate are always welcome....

The alternative will be to uninstall all the lots (using Clean Installer - you can remove them from there). Then also take the cc that came with the lots separately out of your dl folder.
Then install one lot at a time, playtesting each one. Sounds like a lot of work, but it is sooooo worth it.
Strongs!

Good idea, I was already testing lots one by one so it's not even really much more work... And I've been sitting here trying to solve problem almost nonstop anyway. Tracking down all CC from 17000 downloads and no subfolders just won't be that fun. Thanks to you all! If I had been alone, I'd most likely have gone mental by now.