“The file size exceeds the limit allowed and cannot be saved”
The WebClient service refuses to download files larger than 50,000,000 bytes — about 47 MB — by default. The limit is a registry value:
HKLM\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
FileSizeLimitInBytes (DWORD) default 50000000, maximum 4294967295Set it to the maximum and restart the service (net stop webclient then net start webclient, as administrator). The maximum is 4 GB minus one byte: the value is a 32-bit number, so larger files cannot pass through this client at all.
The drive will not connect
- The WebClient service is not running. It starts on demand on client editions and is not installed by default on Windows Server, where it is added as the WebDAV Redirector feature.
- The server uses plain HTTP. Windows refuses basic authentication without TLS by default (
BasicAuthLevel= 1). The right fix is HTTPS on the server, not lowering the setting. - The certificate is not trusted. A self-signed certificate must be installed in the machine's trusted root store, or the mapping fails with a misleading “network name cannot be found”.
- Two-factor authentication on the account. Use an app password; the WebDAV client cannot answer a second-factor prompt.
Folders open slowly
Two causes are common. First, automatic proxy detection: in Internet Options → Connections → LAN settings, clear Automatically detect settings if you do not use a proxy — each request otherwise waits for a detection time-out. Second, the client asks the server about every entry when Explorer builds thumbnails and icons; a folder with thousands of files will always be slow through it, because nothing is cached between visits.
Uploads fail or start over
The WebClient service copies a file to a local temporary folder and sends it to the server in a single request when the program closes it. Explorer shows the copy as finished while the real upload is still running. If the connection drops or the server times out, the whole file is sent again — or silently lost. There is no setting for this; it is how the client works.
The limits no setting removes
| Limit | Built-in WebClient | Can it be changed? |
|---|---|---|
| Largest file | 4 GB | No |
| Resume after a broken transfer | None | No |
| Chunked upload (Nextcloud) | Not used | No |
| Local cache between sessions | None | No |
| Offline access | None | No |
| Future development | Listed by Microsoft as deprecated | — |
When the built-in client is not enough
Pier replaces the WebClient service for the drives you give it. It talks WebDAV itself — over HTTPS with the system proxy settings — and mounts the result as a drive letter through the Dokany file-system driver:
- No client-side file-size limit; on Nextcloud large files go up in chunks.
- A transfer interrupted by a network change resumes from the last completed block.
- A block cache on your disk makes the second visit to a folder or file fast.
- An offline mode keeps cached files usable without a connection and uploads the changes later.
- Before the first mount it checks the server and reports what it can and cannot do.
Setup takes a few minutes: see Mount Nextcloud as a network drive in Windows — the steps are the same for any WebDAV server.