Someone PLEASE help me, because I have a problem that is extremely important for me to fix!!! I need to install a version of Visual Studio with the .NET Core (NOT the Framework or whatever the previous thing was called, so it needs to be at least version 2015 or later!) onto an air-gapped computer (one which is disconnected from the Internet or any other network). The computer MUST NOT be connected to the Internet under any circumstances, and that's non-negotiable, so please don't suggest it (incidentally, this is the same reason why GOG being DRM-free is such a great thing for me). I'm sorry if that sounds harsh but people sometimes suggest things that I just can't do and it's a waste of time.

I've made some progress so far, but every step of the way has been an agonizing experience! I'll give you a quick summary (as quick as it can be) of everything that I've tried up until this point, so that we won't waste time on things that have already been done or tried:

I tried downloading the newest version from Microsoft, but it was a small file that expected to download all of the rest of the files during installation, which obviously won't work.

I considered a long process of installing it on a different computer (specifically this one, which is obviously connected to the Internet) and then migrating it to the other one, but that looked like a huge headache. Fortunately, someone found a web page for me:

https://www.ryadel.com/en/visual-studio-2019-vs2017-vs2015-vs2013-vs2012-older-download-iso-offline-installer/

This provides links to offline installers of various versions of Visual Studio! It only goes up to version 2015 because supposedly, anything newer than that doesn't exist as an offline installer (stupid Microsoft!). But that's alright, because version 2015 supposedly uses the Core, which is supposedly cross-platform compatible with other operating systems like MacOS, which is just what I need! I downloaded the Community Edition (I could get the Professional or Enterprise Edition but I figured that it might require registration or have a built-in expiration, and I only need something basic for what I'm doing, so I thought I'd play it safe - actually though, I also downloaded the Enterprise Edition just in case).

The file is more than 7 GB so it had better be the whole thing! I tried to copy the file onto a portable drive and then put it on the other computer, which caused a problem as well, because it said that even though there was enough space on the drive, the file was too big to be put into its FAT32 file system, so I cut it into a bunch of pieces, put it on the drive, moved it to the other computer and reassembled them into one file. I'm certain that I did it correctly, so it shouldn't be a problem.

Anyway, it's an ISO file, and somehow I've never actually had a need to deal with those. I've always been vaguely familiar with them but I didn't know how to use them because it was just never necessary for me. So I looked up how to deal with it on these pages:

https://www.lifewire.com/iso-file-2625923

https://www.howtogeek.com/356714/what-is-an-iso-file-and-how-do-i-open-one/

https://blogs.technet.microsoft.com/odsupport/2011/04/19/how-to-extract-the-contents-from-an-iso-file-without-burning-the-iso-to-disc/

Supposedly I can just burn it to a disc. I have a DVD burner, but the file is over 7 GB and a DVD can only hold something like 4.3 GB, so I don't think that would work. And I don't have a Blu-Ray burner. So instead, I read about how to mount the file and treat it like it's a drive, so that I can install it from there. Supposedly I need some special software to do it, and the third link above provides one program that it recommends (Pismo) and lists four other programs as well. I downloaded Pismo and installed it on my offline computer, but it didn't seem to give me the option to mount, like the third link above says that it's supposed to add to the right-click menu for the icon. When I try to run the Pismo program directly, I get a generic Windows error that it crashed and must be closed.

So I looked at the other tools instead. I couldn't find anything useful on the Daemon Tools site, and the link for CDmage wouldn't load. So I got IsoBuster and Winrar, and installed them both.

I tried Winrar first because that's a good, reputable program. I checked the box to associate ISO files during installation, and then I tried a similar mount option that it added to the right-click menu, but it didn't seem to cooperate at all. So I decided to just extract the files from the ISO into a folder and then run the installer from there. I know that it's not necessarily likely to work if I do that, because it may expect it to be running from a drive (like if you just copy a bunch of files from a CD to a hard drive and then run the installer, it will generally show an error saying that it can't find the CD or something like that), but I was desperate so I wanted to try anything that might work.

So after I extracted the files to a folder, I took a look inside, and there was a small installation file, but with it were a few folders, and one contained many more folders with lots of files, totaling about 7 GB, so I figured that all I need is in that folder. I went to run the installer, and it said that the computer isn't connected to the Internet and should be, so that the installation process can go smoothly! This is the exact thing that I was trying to avoid by using an offline installer, otherwise what's the point?!

But it also said that it doesn't have to be connected to the Internet and I can still attempt installation anyway, but if I try to install anything which isn't included then I may get an error. So I proceeded, looked at the customization of which files should be installed, and unchecked anything which isn't absolutely necessary (I didn't even install ASP.NET stuff, since I only need plain C# for making offline programs).

This part's weird. When I tried to install, every file that it attempted to install gave me an error, and sometimes I could click a button to skip it or retry it, and when I clicked one it would make the screen look like it's sliding to the right to allow the regular installation interface with the load bar to take it's place. But retrying never did any good, and sometimes it would only let me retry or only skip, and it would disable other options! And then after skipping a couple of files it got stuck on retry, so I couldn't go any further, and it started giving me the error before sliding back more than a small fraction of the width of the window, so that it wouldn't show the installation interface at all - only the error where I could retry.

At this point I decided to undo/cancel the installation, but the cancel button is only on the main installation interface, which it wouldn't display! So I had to press and hold the Enter key, so that it would attempt to retry a file so rapidly that the screen would slide back to the main installation interface slightly quicker than the errors kept popping up and causing it to slide away, resulting in a gradual sliding to the right of the error screen to reveal the main installation screen until it was just visible enough that I could click the cancel button and abort the installation!!!

So that all went nowhere. Then I decided to try IsoBuster, which seems like a DOS program that I have to run from the command prompt and give it parameters for an ISO file as an input and another file as an output, presumably the mounted version, I guess (?), but ultimately it gave me an error and didn't work. The weird thing is that it seemed to expect a WAV file, or wanted to generate a WAV file, or something, which is weird, because I'm not dealing with sounds at all, and I don't see how that would be relevant.

Anyway, could someone PLEASE just tell me once and for all how to mount and install this damn ISO file on my offline computer so that I can use Visual Studio 2015 on it??? Thank you!!!

I always use wincdemu (https://wincdemu.sysprogs.org/). It's open source.

Btw. I did the exaxt same thing (install VS2015 on an offline pc) several years ago. I documented my steps. Give me a moment and I pm you.

edit: oh didn't read about FAT32. If you don't have a REALLY REALLY good reason to use that filesystem, I strongly suggest you switch to NTFS beforehand. You will save yourself (and us) al lot of headaches...

FAT .............. Talk about a blast from the past. Well you must have reasons.

How about an empty USB stick, 8GB+ in size? Use any advanced unpacker to extract the files in the ISO unto the stick. Maybe that will work better.

Cannot help more than that as other methods fly over my head.

FAT really blocks you from handling any files sized over 4GB. Otherwise mounting it would be so easy.

So, this topic again, I believe we went over this all some months back didn’t we?

As stated above you use mounting software (wincdemu is also what I use), to load a disc image (iso is one type of disc image file, there are others). When that is installed, right click on the iso, and select mount to drive letter, it will then open as if it was a cd, very simple.

Now onto visual studio. It’s presented as a stub installer as the program itself is huge, formed by many different parts, and it’s really not advisable to try to install parts on your own, it will just be headaches. This is why it is given this way. Also, as with most software nowadays, it expects to phone home for various things, like additional components, other tools etc. Installing it on a non connected computer is drastically limiting what it will be able to do with manual effort each time.

Simple fact of life now is that apps need internet connection, save yourself all the trouble and install the latest vs via the web to a computer, would have saved you months of wasted effort.

For example, I recently had to modify some .net code for work. Jumped onto M$ site, downloaded installer, let it run for 15 mins. Set some options and components, let it install more. Then jumped into studio, added some extra third party components to the framework to allow for additional functionality, and was off and away in less than an hour.

I also support Wincdemu and Daemon Tools Lite. You have to configure the virtual drives in Daemon Too,s Lite before you.can mount an ISO to the drive.

I'll check that out tomorrow, thanks! I didn't get a message from you. Maybe just post it here if that's alright? Because then other people can see it if they have the same problem. But if you want to tell it to me privately that's fine too. Actually, the reason that I'm using that is because it just happens to be how the drive is formatted. I didn't even realize that until I got the error. It's fairly old, but I don't remember when I got it. I know that it's newer than NTFS though, so I don't know why it's formatted that way. I don't think that I have any other portable drives at the moment which aren't already used for other purposes. I'll see if I can switch to NTFS, but I'm not sure why it would matter, because after I put the file on the portable drive, I just transfer it to the offline computer which is running Windows 7, so I doubt that it's using FAT on its hard drive. That's not a bad idea! I could just burn the ISO directly onto a portable drive rather than mounting it as a file on the main hard drive. Unfortunately, like I said, I don't have any extra 8+ GB drives at the moment and I'm not sure how soon I'll be able to get one (I think I have several old 4 GB drives, but that won't do any good). Yeah, which is the reason why I had to split the file into smaller pieces and then reassemble it. At first I thought it was complaining that there wasn't enough space on the drive, even though I had like 24.6 GB free, so I was like "WTF?!". Yes we did, and I had gotten what I thought was all the information that I needed, but when I looked back through the links to web pages that I had saved, and followed the instructions, it turned out to cause new problems that I hadn't anticipated. I just hadn't done all of this back then because I got sidetracked by other things and had to eventually get back to it (I've been fairly busy for a while). But now it's getting to a point that I'd really like to resolve this very soon if possible. Yes, I know. But as I stated, after installing the mounting software (the one that I got was something called Pismo), I was not given the option to mount, because it didn't appear on the right-click menu like it's supposed to. I really only need the most basic functionality so that I can upgrade a single, very simple C# program, which doesn't even use any external libraries at all to my knowledge, so that I can make it compatible with MacOS in addition to Windows (it's currently only compatible with Windows because it's compiled in Visual Studio 2012). And for security purposes, it absolutely may NOT be put onto a computer that is connected to the Internet. Sorry, but there's no way around that. See above. That's all well and good, but I don't see why I can't even install a basic version that will just simply give me the ability to compile my damn program for .NET Core compatibility. Or alternatively, is there a program that will allow me to upgrade an existing .NET EXE file from version 2012 to version 2015 or later?

I recommend that you normally format any USB stick larger than 4GB as ExFAT, a modern file system for USB sticks. I think they still sell them formatted as FAT32 for compatibility with old operating systems. Occasionally you need a stick that must be in FAT32 format. (Hey UEFI update)

geeez

I'm not suggesting such, but you won't connet your PC to the net for a few minutes to DL and install an official MS file, and would rather go to "extreme" lengths to do so? My hat is off to you, at the very least, but that seems a tad overkill.

Most times once could just install a good AV and keep it running and scanning all incoming files, connect to the net/update, and they'd be just fine/safe while doing so.

Regardless, I list a solution below(if you're using older Windows OSs)....I hope it helps. Did you try Alcohol free version?

It should work with most older versions of Windows(7/Xp/etc) and mounts a virtual drive one can then mount an iso to(by right clicking the newly made virtual drive in their drives list and clicking mount/etc and picking the disc image). With many drives now having 64-128 GB for around 10-20 bucks I would recommend you get one if you can. Gov't work or what? Because I don't see why one would need that level of security otherwise.

(I don't expect you to answer or want you to feel like i'm forcing you at all...i'm just voicing my curiosity)

If you have Windows 8 or higher installed on that computer you should be able to just double-click on the ISO, and it automatically mounts it to a directory. In the past though, Daemon Tools has always worked well for me.

For DVDs, you can pickup dual layer discs, which will hold over 8GB if you need to burn the file. I've found that DVD-R seems to have a higher compatiblity rate with drives over the DVD+R.

Are you be able to use some sort of software similar to Virtual Box or VMWare on this computer? If so, you could create a Virtual OS on another computer with Visual Studio installed (just use evaluation versions for the OS), copy the hard drive image, and then load it up on the offline computer? You can then destroy that USB stick after using it for what you need, so technically no data ever leaves.

This is what I used to mount ISOs in Windows 7:
https://wincdemu.sysprogs.org/

I see it's already mentioned.

Yeah, but thanks anyway. I'll consider it another vote for that program, and I'll look into it right after I eat, which I'm about to do.

Well, I just downloaded and installed the WinCDEmu program on this computer just to test it, and it seems to be able to mount just fine! I don't have time to do more today, but tomorrow I'll put it on the other computer and try to mount the file there, and then see if it actually installs from there.

However, I do have a fear that it might not, because I mounted the same ISO file on this computer, and when I opened the new "drive", it showed the same files with the same installer in the same way, so I don't know - it just seems like if I couldn't get it to install before, why would it necessarily work this time?

What I'm hoping is that the only reason why it didn't install before was because it was just a folder on the hard drive, rather than being mounted properly as a DVD drive itself (that's how I did it as a test this time, because it gave me a bunch of choices of what type of drive I wanted, and I assumed that was the right one, but please correct me if I'm wrong).

But anyway, I'll try it tomorrow, and see whether it works. Now I just have to keep my fingers crossed until then, which is a bit tiring for my hands, but oh well.

Basically it's a program that allows you to create a virtual hard drive as a file. Through the program, you mount an ISO onto a virtual drive (from within the program), boot it, and it will act like a PC inside your PC. It's all done through a window. It's a great way to test out different operating systems, or play with a server environment by having multiple virtual machines running on the same system. It's basically how I studied for my Server certs back in the day.

Here's the link for VirtualBox, which is open source.
https://www.virtualbox.org/

Here's a link to a tutorial on using it.
https://www.youtube.com/watch?v=sB_5fqiysi4

As for putting it on a USB drive, yes that would be quicker and work better. You should be able to copy the files out of the ISO after it was mounted right onto the USB stick, and then run the install from there. Otherwise, mount the ISO on the PC you're working on. The advantage of having a virtual machine is that you can essentially carry a small work computer with you on a USB stick and run it on any computer you work on (as long as that computer is running).