How Many PCs Can Share Files on a Local Network at Once?
Windows, macOS, and dedicated NAS devices all have different simultaneous connection limits for file sharing. Here is what those limits are and when they actually matter.
The Short Answer
Connection limits for local file sharing:
| Host type | Max simultaneous connections |
|---|---|
| Windows 11 Home | 5 |
| Windows 10/11 Pro | 20 |
| Windows Server (any version) | Unlimited (licenced per seat) |
| macOS Ventura / Sonoma (File Sharing) | Up to 10 users |
| Synology NAS | Model-dependent; typically unlimited for SMB |
| QNAP NAS | Model-dependent; typically unlimited for SMB |
But the connection limit is rarely the actual bottleneck for small offices. Read on to understand what actually constrains performance at scale.
Windows Home: The 5-Connection Limit
Windows 10 and 11 Home editions enforce a hard limit of 5 simultaneous SMB connections to a shared folder. This is a Microsoft licensing distinction to push larger deployments toward Windows Server.
In practice: a "connection" in this context means an active SMB session, not a user. Opening a file in Word across the network counts as a connection for the duration the file is open. If all 5 slots are occupied and a 6th machine tries to connect, it receives an error: "No more connections can be made to this remote computer at this time."
For a team of 5 or fewer: this limit is unlikely to cause problems in practice, since not all 5 people typically have active SMB sessions simultaneously.
For a team of 6+: Windows Home as a file server becomes unreliable. Solutions:
- Upgrade the host to Windows Pro (allows 20 simultaneous connections)
- Move to a NAS (no meaningful SMB connection limit)
- Use an application-level transfer tool that bypasses the SMB connection limit
Windows Pro: The 20-Connection Limit
Windows 10 and 11 Pro permits 20 simultaneous SMB connections. For most small offices (2–15 people), this is sufficient. The 20-connection limit is rarely reached because connections are counted per active session, not per user who has ever mapped the drive.
For offices approaching or exceeding 20 simultaneous users: a NAS or Windows Server is the appropriate upgrade.
macOS File Sharing Limits
macOS limits incoming SMB connections to approximately 10 simultaneous users. For small offices where a Mac is acting as the file host, this is adequate for teams of 10 or fewer.
In practice, Mac-hosted shares are less common in office environments. When used, the 10-connection limit is rarely a constraint at small office scale.
NAS Devices: Effectively Unlimited for Small Offices
Business-grade NAS devices (Synology, QNAP, Asustor) do not impose meaningful SMB connection limits at small office scale. A Synology DS923+ handles 20–50 active SMB connections comfortably without performance degradation.
The limiting factor on NAS devices is throughput and disk speed, not connection count.
What Actually Limits Performance at Scale
Even if the connection limit is not reached, network file sharing degrades at scale for other reasons:
Network switch throughput: A gigabit switch has 1 Gbps per port but a limited backplane capacity. Most consumer and prosumer switches handle 10–20 simultaneous gigabit connections without degradation. Enterprise switches have higher backplane capacity.
Disk I/O on the host: If 10 people are simultaneously reading large files from a single spinning HDD, the drive's read throughput (100–130 MB/s) is split between them. Each user sees 10–13 MB/s effective throughput — barely adequate for large file work. SSD-based hosts or NAS units with SSD caching significantly improve this.
CPU on the host machine: For SMB3 encryption-enabled connections, the host machine's CPU handles encryption/decryption for every active connection. A modern desktop CPU handles this easily for 5–10 connections. For 20+ simultaneous encrypted connections, a dedicated NAS with hardware AES acceleration is more appropriate.
Application-Level Tools and Connection Limits
Tools like Oxolan and LocalSend are peer-to-peer — each transfer is a direct connection between two machines, not a one-to-many relationship through a central host. There is no connection limit in the same sense as SMB host connections.
Each machine connects directly to the machine it wants to receive a file from. A 15-machine office has 15 independent Oxolan instances, each able to send or receive simultaneously. The limit is the available network bandwidth, not a connection cap.
When You Actually Need Windows Server
Windows Server becomes the appropriate choice when:
- More than 20 simultaneous users need shared file access
- You need Active Directory for centralised user management
- You require DFS (Distributed File System) for multi-location file access
- Compliance requires detailed access audit logs at scale
For small offices, the jump from Windows Pro (20 connections) to Windows Server is significant in cost and management overhead. Most small offices should evaluate a mid-range NAS before considering Windows Server.
Practical Limits for Common Office Sizes
| Office size | Recommended host | Notes |
|---|---|---|
| 2–5 people | Windows Pro machine or any NAS | Home is fine if connections are light |
| 5–10 people | Windows Pro or entry NAS | Windows Home risks hitting 5-connection limit |
| 10–20 people | Mid-range NAS preferred | Windows Pro technically works but NAS is more reliable |
| 20–50 people | NAS or Windows Server | Performance and management needs exceed simple setups |
| 50+ people | Windows Server + infrastructure | Consult an IT professional |
Frequently Asked Questions
Does each mapped drive count as a connection? A mapped drive that is not actively being used does not count as a connection in most Windows SMB implementations. The connection counter increments when active data is being transferred, not when a drive is simply mapped.
Does the number of files shared affect the connection limit? No. Connection limits are based on active sessions, not the number of files or folders being shared.
Can I increase the Windows Home connection limit without upgrading? Not officially. Third-party workarounds exist but are unsupported and technically violate Microsoft's licence terms.
If I use a NAS, do all machines need to be on? No. The NAS is always on (or on a schedule you set). Individual workstations do not need to be running for other machines to access the NAS — this is the primary advantage over a shared folder on a regular workstation.
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