Fix the Windows WebDAV 50 MB File Size Limit (Error 0x800700DF)

Windows stopped the copy, not your server

You map a WebDAV drive in File Explorer, drag a 180 MB video onto it, and the transfer dies before the progress bar has anything to show. The message is 0x800700DF, "The file size exceeds the limit allowed and cannot be saved."

Nothing on the server side refused that file. The refusal happened locally, on your own machine, before a single byte went out.

Every mapped WebDAV drive on Windows is handled by a service called WebClient, and WebClient carries a registry value named FileSizeLimitInBytes. On a clean Windows install that value is 50,000,000 bytes. Fifty million in decimal, which works out to roughly 47.7 MiB. Documents never hit it. Videos, database dumps, disk images and layered design files hit it constantly.

One note for anyone searching, because it sends people down the wrong path. A lot of forum threads call this the WebDAV 50 GB limit. It is not 50 GB. Three zeros went missing somewhere years ago and the mistake keeps getting copied.

Raise FileSizeLimitInBytes

You need administrator rights on the machine, and the change applies to every WebDAV mapping on it, not just one.

Open regedit and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters. Find the value named FileSizeLimitInBytes, or create it as a DWORD (32-bit) value with exactly that name if it is missing. Double-click it, switch the base to Decimal, and type the ceiling you want in bytes. Two sane choices are 4294967295 for the maximum, or something like 2000000000 if you would rather keep a deliberate cap.

Then restart the service. WebClient only reads that value at startup, so the new number does nothing until you do. In an administrator command prompt, net stop WebClient followed by net start WebClient is the fastest way. Restarting the WebClient entry in services.msc works the same.

Reconnect the mapped drive and retry the copy.

The ceiling you cannot move

4294967295 bytes is 0xFFFFFFFF, and it is a hard stop. Windows stores that limit in a 32-bit value, so just under 4 GB is as far as the native WebDAV client goes. There is no registry key, no policy and no hotfix that takes it past that.

There is a second failure mode people confuse with the size limit. If a large copy runs for a while and then dies partway through instead of failing instantly, that is usually a timeout rather than FileSizeLimitInBytes. WebClient keeps its timeout values in the same Parameters key, and raising them helps when a slow link needs several minutes to push one file.

The Windows WebDAV 50 MB limit lives in the client, not the server

This matters more than the registry edit, and it is the part most pages skip. FileSizeLimitInBytes belongs to WebClient. The WebDAV server on the other end has no idea the value exists.

AnyStorage runs a WebDAV server on your own machine. Open Services in the sidebar, switch to the WebDAV tab, press Start, and you get http://127.0.0.1:3211 with HTTP Basic auth always on — default username anystorage, and a 24-character password generated on first use, both editable, both with copy buttons. Every storage connection you currently have open in the app appears as a folder at the root of that URL, whether it is an S3 bucket, Cloudflare R2, Google Drive, OneDrive, or an SFTP host. Twenty connection types can be exposed this way.

That server streams reads with HTTP range support and streams writes without buffering whole files in memory, so it imposes no size cap of its own. Point any third-party WebDAV client at the same URL and a 3 GB file moves without touching regedit. For files past 4 GB, or for bulk moves of any size, skip the mount entirely and do the transfer inside the AnyStorage app, which talks to the storage backend directly and never involves WebClient.

A few things we would rather say up front than bury:

• On the free tier the WebDAV server is read-only, so you are reading out of the mount rather than writing into it. The 50 MB cap applies to that direction too. Read-write is a Pro feature.
• The same WebClient service that caps file size also refuses HTTP Basic auth by default. Mapping an http:// URL may need BasicAuthLevel set to 2 under the same Parameters key, plus another service restart.
• There is no TLS in the current version, which is exactly why we bind to 127.0.0.1 by default and warn loudly before enabling LAN access.
• After you restart the app, a connection shows up under the WebDAV root only once you have opened it in the app that session. Connections connect lazily.

Which route to take

• Files under 50 MB. Nothing to change, the default is already enough.
• Files up to 4 GB, and you are fine editing the registry. Set FileSizeLimitInBytes, restart WebClient, done.
• Files past 4 GB, or a machine you cannot make registry changes on. Use a third-party WebDAV client against the same local URL, or move the file in the app itself.

The pattern to remember, as of 2026, is that WebClient is deprecated and full of decade-old defaults. When a WebDAV transfer fails on Windows and works everywhere else, suspect the client first.