Managing files efficiently is essential for smooth operations across different systems. Enforcing filename, length, and extension restrictions on newly uploaded files helps prevent errors, ensure compatibility with external systems, and reduce security risks.

These restrictions on the folder apply only to files at the time of upload.

Many external systems, counterparties, and remote servers have their own filename and file type restrictions. Enforcing these rules at the source helps avoid failed transfers, disruptions, and compliance issues. A structured file-naming approach also improves scalability and performance as file volumes grow, making it easier to manage files in the long run. It also enhances automation reliability, ensures consistent processing, and improves user experience by keeping files organized and accessible.

Use Cases

Here are some common scenarios where applying filename, file type, or folder structure restrictions can help prevent errors, maintain compatibility, and protect your workflow.

Operating System & Cross-Platform Compatibility

Different operating systems have filename restrictions. For example, Windows does not allow characters like \ / : * ? " < > |, while UNIX-based systems may enforce limitations on special characters or case sensitivity. A filename that works in one system may cause errors or be inaccessible in another (e.g., Linux vs. Windows). Enforcing filename rules using Limit Uploaded Files to Regular Expression helps ensure seamless file transfers across platforms.

Counterparty & Workflow Compatibility

Some external systems and workflows only accept specific file extensions. If an unsupported file type is uploaded, these systems may fail, crash, or behave unpredictably. Enforcing restrictions using Limit Uploaded Files to Certain File Extensions ensures files remain compliant with expected formats.

Remote Server Limitations

Certain remote servers do not support specific file types, symbolic variables, or filenames exceeding a defined length. Using Limit Uploaded Files to Certain File Extensions or Limit Uploaded Files to Regular Expression prevents upload failures and unexpected behavior when interacting with these servers.

File Name Length Restrictions

Many systems impose filename or path length limits, and exceeding these can cause transfer or processing errors. Enforcing restrictions using Limit Uploaded Files by File Name Length helps prevent issues caused by excessively long filenames.

Preventing Disruptions in Automated Workflows

If your team relies on automation, such as scheduled syncs, file transfers, or integrations with external systems, an accidental folder move can cause failures or misrouted data. Locking subfolders ensures that workflows function without unexpected interruptions.

Protecting Shared Project Directories

In collaborative environments, project files may be stored in a structured hierarchy. If a user unintentionally moves or renames a folder, team members may lose access to essential files or disrupt version control. Locking the folder structure ensures everyone can access files as expected without modifying the organization.

Security & Hidden File Considerations

Restricting certain file types helps prevent the accidental or malicious upload of executable files (.exe, .sh, .bat), scripts, or hidden files (e.g., .filename) that external systems may ignore or block. Using Limit Uploaded Files to Certain File Extensions or Limit Uploaded Files to Regular Expression ensures only safe and intended files are uploaded.

Compliance & Regulatory Requirements

Certain industries require strict file controls to comply with HIPAA, GDPR, or SOX. Using Limit Uploaded Files to Certain File Extensions ensures that only permitted file types are stored or transferred, minimizing regulatory risks.

Symbolic Variables & Naming Conflicts

Some counterparty systems use symbolic variables (e.g., $, %, {}) in filenames for automation or templating. Allowing unrestricted filenames may cause misinterpretation, conflicts, or unintended execution of system commands. Using Limit Uploaded Files to Regular Expression prevents filenames containing such characters.

Moving or Copying Files into Restricted Folders

Moving or copying folders into destination folders with filename or length restrictions is not allowed. This includes restrictions based on specific file extensions, filename length, or regular expressions. These filename or length restrictions apply only to files or folders that are directly uploaded to a folder, not when they are moved or copied into it.

If you use a Files.com automation that requires special handling on the source file names, refer to File Name Pattern Matching. For renaming destination files, see the guidelines on customizing destination filenames.