Bugs and Limitations

Limitations

Directory timestamps aren't preserved on some backends

As of v1.66, rclone supports syncing directory modtimes, if the backend supports it. Some backends do not support it -- see overview for a complete list. Additionally, note that empty directories are not synced by default (this can be enabled with --create-empty-src-dirs.)

Rclone struggles with millions of files in a directory/bucket

Currently rclone loads each directory/bucket entirely into memory before using it. Since each rclone object takes 0.5k-1k of memory this can take a very long time and use a large amount of memory.

Millions of files in a directory tends to occur on bucket-based remotes (e.g. S3 buckets) since those remotes do not segregate subdirectories within the bucket.

Bucket-based remotes and folders

Bucket-based remotes (e.g. S3/GCS/Swift/B2) do not have a concept of directories. Rclone therefore cannot create directories in them which means that empty directories on a bucket-based remote will tend to disappear.

Some software creates empty keys ending in / as directory markers. Rclone doesn't do this as it potentially creates more objects and costs more. This ability may be added in the future (probably via a flag/option).

Bugs

Bugs are stored in rclone's GitHub project: