.. index:: single: git-annex; transfer lock KBI0027: "Transfer already in progress, or unable to take transfer lock" ======================================================================== :authors: Adina Wagner :discussion: :keywords: transfer lock, datalad get, data retrieval :software-versions: datalad_0.19.2, git-annex_10.20221003 When retrieving or uploading data, users can in rare cases see a failure together with the message ``Transfer already in progress, or unable to take transfer lock``. This message originates in lock files git-annex uses to keep several transfer processes from interfering with each other. Usually, it should suffice to wait a bit until the process that holds the lock open exits and releases the lock automatically. But in some cases, e.g. when CTRL-C'ing a process unluckily or on Windows, the lock file can get stale, and the error message remains regardless of how long one waits. When this happens, do the following: - Be sure that there is no git-annex process that holds the lock open for a good reason. You should check the processes running on your system, and - when transferring data to a remote system - also the processes over there. - If you are sure that the lock is stale, remove the files inside of ``.git/annex/transfer/``, and retry. A short discussion for further reading can be found `here `_.