File.Move for filepaths longer then 260 characters

I need to rename some files in my application that are placed somewhere on the pc.
First I am getting every file path in a directory. And then I use File.Move to rename it.

Every file path that is longer then 260 chars would not work and would give me an error saying the file does not exist.

FileNotFoundException: "Some/300/characters/long/path.png" does not exist

However Directory.GetFiles IS actually retrieving the files with the long names.

I can also log the file path and go to it in Windows explorer. And therefore I can verify it really does exist. I have verified that the problem is the path length.


I can not manually shorten the file name, because it needs to work dynamically with all possible files. And non-coders need to use the software, using their own images.

Code (CSharp):

1.                 foreach(string file in Directory.GetFiles(folderpath))
2.                 {
3.                     File.Move(
4.                        file,
5.                        newName
6.                         );
7.                 }

How can I rename, or read a file that has a longer file path then 260 characters?

 

That's a windows system limitation - you can apparently try to get around it by prefixing \\?\ to the path so:

"\\?\D:\Some/300/characters/long/path.png"

Seems weird as heck to me but try and let me know if that helps.

You can read more about the path length limitations here: https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=cmd

 

Hi Thanks,

I did already try that out. But doing that it won't recognize any file anymore. So it doesn't seem to pick up that prefix as I intended.

 

Hmm damn - sorry that didn't help. Fascinating problem - hope someone comes along with an answer cause now I wanna know.

 

Nevermind! It worked!

\\?\ wasn't working for me because my path name also contained / instead of using only \
So I converted the file path:

Code (CSharp):

1. file.Replace("/","\\");

And now it works with the \\?\ prefix.

Thanks a lot!

 

@Rob-Reijnen That's wild! - really surprised I've never encountered this before.

 

Just encountered it throws my commit of. Has ANyone found a solution?

 

This post is incredible. Solved my long path issue as well.

Thanks @Cameron_SM and @Rob-Reijnen for both of your efforts!

 

Hi All,

I also had the same FileNotFoundException when I tried to write a more than 259 chars long file path.

I started using this "\\?\" prefix, and use only "\" chars, but I get this error:
Win32 IO returned ERROR_INVALID_NAME. Path: \\?\D:\SquareLine Projects\Empty\components\aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaarrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaqwertzuiop.ecomp

Does anybody have an idea?

Thanks

 

There are two limitations at play here. The 260 character limit is an API limit that is the result of backwards compatibility. A lot of Win APIs are still bound to this limit but there are workarounds / different APIs that work with longer paths. However this 260 character limit affects the whole path. There are additional limits for how long individual filenames can be. This depends on several factors, mostly the file system. NTFS has a limit of 256 characters per entry. So individual file and folder names can't be longer than 256 characters Your filename

aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaarrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrraaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaqwertzuiop.ecomp

has 263 characters, That's not possible.

So you could have 5 nested folders, each with a name of say 200 characters and a filename with 240 characters which would give you a path length of 3 + 5*200 + 240 == 1243 characters and this should work with the prefix. However a single entry in the path must not be longer than 256 characters.

ps: The "260" limit actually was also 256. It's the path without the drive (D:\) and without the null terminating character that most WinAPIs require.

pps: Why would you need a file name that is longer than 256 characters? That's just insane ^^

 

You're running into the limitation of the maximum path length in Windows, which is indeed 260 characters. However, since .NET Framework 4.6.2 and .NET Core 2.0, there's a way to overcome this limitation by using the `\\?\` prefix to specify an extended-length path. Here's how you can modify your code to handle long file paths:

```csharp
foreach(string file in Directory.GetFiles(folderpath, "*", SearchOption.AllDirectories))
{
string newFilePath = Path.Combine(folderpath, "newname.txt"); // Modify this to generate the new file path dynamically
string extendedFilePath = @"\\?\" + Path.GetFullPath(file); // Prefixing with \\?\ to support long paths

File.Move(
extendedFilePath,
newFilePath
);
}
```

Here are the changes made:

1. Use `SearchOption.AllDirectories` to search recursively through all directories.
2. Prefix the file path with `\\?\` to enable support for extended-length paths.
3. Generate the new file path dynamically according to your requirements.

This should allow you to handle file paths longer than 260 characters.


Or you can use LongPath Tool, simple as that.

 

I used this above code:

```csharp
foreach(string file in Directory.GetFiles(folderpath, "*", SearchOption.AllDirectories))
{
string newFilePath = Path.Combine(folderpath, "newname.txt"); // Modify this to generate the new file path dynamically
string extendedFilePath = @"\\?\" + Path.GetFullPath(file); // Prefixing with \\?\ to support long paths

File.Move(
extendedFilePath,
newFilePath
);
}
```
but it didn't work. Then, I installed Long Path Tool. It has helped though.

 

Has anyone found the solution yet? Character path limit can easily be solved by various tools. Has anyone used any of the tools such as longpath tool?