File is locked by... on Raspberry Pi with external HDD in Sync Troubleshooting Posted June 1, 2019 · Report reply Hello! I have a problem and need your help. - I installed Resilio Sync on Raspberry Pi 3, set it to boot on start - added two external HDDs with exFAT and NTFS file systems - added tools to work with file systems and change config to mount external drives on boot. And all were good for day or so. Now I have no sync and have regular messages "file is locked by another application" for every file sync tries to read/write. - I removed folder from sync, deleted .sync folder, reboot, add folder again and it works for hour or two. Then it appear again, files locked, on both HDDs - meanwhile I can open HDDs folders on Raspberry anytime, can read and write the files - I have no other software in the system except Sync - rslsync is in root group and drives permissions are 0777 - I tried to disable power management for HDDs with "hdparm -B255" - without luck. Any ideas how I can solve this problem?