File Selection

A Sync first decides which source paths are eligible, then compares their names and sizes with the destination to determine which files need transferring. Filters, case comparisons, and the metadata supplied by a Remote Server all affect that decision. A schedule determines when the comparison runs; it does not change how files are selected.

Filename and Size Comparison

Files.com uses filename and file size to determine whether a file needs to be synced. It does not use modified dates or checksums for this selection.

This methodology works consistently across the wide variety of remote server types Files.com supports. It determines which files to transfer; it is separate from the integrity checks performed during transfers. A file whose contents change but whose name and size stay the same is not selected by this comparison.

The same comparison affects source cleanup: with After Copying set to delete, an existing destination file with the same name and size can cause the source to be deleted without another transfer. Matching names and sizes do not establish identical contents.

Include and Exclude Patterns

The Include Patterns and Exclude Patterns settings let you selectively copy items from the source to the destination of your sync.

Without patterns, all source paths are eligible. The filename-and-size comparison still determines which eligible files need copying.

Include Patterns

Use glob patterns to define the items that will be included in the sync.

If set, only path names matching one or more of these patterns are synced. Path globs use the syntax documented for v1 source patterns and v2 file selection. Prefix patterns with **/ to apply them to filenames in any folder or subfolder.

Multiple include patterns can be configured for a single sync.

Exclude Patterns

Use glob patterns to indicate items that will be excluded from the sync. If set, any path names matching one or more of these patterns are ignored and excluded from the sync.

This setting takes precedence over the include patterns setting when a path matches both.

When a folder name matches any Exclude Patterns, the entire folder is not copied. All contents of the folder, including every recursive subfolder and its contents, are also excluded.

Path globs use the syntax documented for v1 source patterns and v2 file selection. Prefix patterns with **/ to apply them to filenames in any folder or subfolder.

Multiple exclude patterns can be configured for a single sync.

Glob Pattern Matching

Glob patterns let you specify the criteria for matching files and folders to be included or excluded with a sync. Globs support both folder path matching and file name matching.

Path Matching

The * matches any folder at that specific level in the path but excludes subfolders, while the double asterisk ** matches subfolders recursively. For example, path/to/* matches path/to/folder1 and path/to/folder2, but not path/to/folder1/subfolder, whereas path/to/** includes all subfolders.

The question mark ? matches any single character. Square brackets [] match any character from a set, similar to regular expressions.

File Name Matching

Specify a pattern for file names to match using standard text with or without wildcards, or file extension matching (like *.pdf).

For example, the pattern matching text *paid* matches any file with a name containing the word 'paid' (case-insensitive).

You can also build an expression to match any single character using ?, or match an array of characters using [].

To match a special character literally, precede it with a backslash and enclose the pair in square brackets. For example, to match a literal ?, use [\?].

A bracket expression matches one character. [a-z]*.csv matches CSV names beginning with a letter, and [^a-z]*.csv matches CSV names beginning with a non-letter. Matching is case-insensitive. Neither pattern restricts the characters matched by the following *.

Curly brackets {} denote parts of a pattern that accept a number of alternatives, separated by commas ,. These alternatives can be literal text or include special characters, including nested curly brackets. For example, *{Mon,Tue,Wed,Thu,Fri}* matches any file whose name contains an abbreviated weekday, and 202{6-{0[7-9],1[0-2]},7-0[1-6]}-* matches filenames beginning with a year and month from July 2026 through June 2027, followed by a hyphen. This checks the naming pattern, not whether the day is a valid calendar date.

Full Path and File Name Matching

You can combine path matching together with file name matching.

For example, to match PDF files within a specific subfolder, you can use a pattern like path/to/subfolder/*.pdf.

To match PDF files within any subfolder, whose name contains 2024 or 2025, you can use a pattern like **/*202{4,5}*.pdf.

Files Changing During a Run

Syncs with object storage remote servers of type AWS S3, Azure Blob, or Google Cloud Storage include an extra file update check.

The sync checks whether a file has been updated since the sync started. If the file was updated, it is skipped from this sync. This prevents partial files from being delivered to the destination while the source is still being written.

A file skipped for this reason records the following message in the Sync Logs:

Detected a change in file during sync

Skipped files are processed again in subsequent syncs. When the same file is skipped run after run, it is being written continuously, or it is being written on the same schedule the sync runs on. Move the sync to a window when nothing is writing to the file.

File Names and Case

Syncs require file and folder names to satisfy both Files.com's naming rules and the destination's restrictions. A name accepted on Files.com can be rejected by a Remote Server, and a name accepted on a Remote Server can be rejected when transferred to Files.com. Rename affected items to meet the requirements of both systems.

Naming failures in either direction appear in the Sync Logs. If Files.com encounters files that would not be allowed on the Files.com side, the Sync results in a Partial Failure.

Case Sensitivity

Syncs use the Files.com case sensitivity rules.

Files.com applies a best-effort approach to make case conversions work intelligently. Perfectly modeling ideal behavior in this situation is not possible.

Because two names that differ only by case are the same name under those rules, a run omits folders that collide and records one of these messages in the Sync Logs:

Skipped due to multiple files/folders having the same case-insensitive name on the source.

Skipped due to multiple files/folders having the same case-insensitive name on the destination.

Source folders named MYSTUFF and mystuff both match a destination folder named MyStuff, and transferring both would merge their contents into it irreversibly, so the sync omits them instead. The destination message means the reverse: several destination folders match one source folder by case-insensitive name, and the sync cannot determine which one is the correct target.

Leave only a single copy of any folder name in the sync source and in the destination, regardless of case.

Remote Metadata Limitations

Filename and size comparisons have limits when another system changes files or reports their metadata differently.

Syncing Files to Microsoft SharePoint

Microsoft SharePoint parses files in order to index and promote them within the SharePoint user interface. Files uploaded to a Document Library are modified by SharePoint to include extra column and value metadata. The file size increases and its modification time is updated, which makes Sync unable to determine if the synced file matches the original.

3play's FTP Server

3play's FTP server reports file sizes incorrectly. Because Sync uses file size to determine whether a file needs to be transferred, syncs against 3play's FTP server produce unexpected outcomes.

Mitigating the Limitations

When filename-and-size selection cannot identify the files your workflow needs, use an Automation with explicit replacement settings instead. A Copy Files Automation needs both overwrite options enabled to replace same-name, same-size files; a Move Files Automation uses its single overwrite option. It can access a Remote Server directly or through a mount. See overwrite settings.

Changing the transfer mechanism does not finish a file still being written, remove a remote file lock, or change the server’s supported sizes and names. Coordinate the producer’s completed-file handoff first and verify the selected transfer against that server. Contact Support when the server’s metadata or transfer behavior still prevents the intended result.