I am running a server 2008 with iis7 and the ftp addon on to iis 7.0

I have the ftp site configured and mostly working

Except that about 70% of the time when transferring a file the upload will hang forever. If I disconnect the ftp client and reconnect and try to upload the same file I will get an error on the client saying the file is locked.

I have to restart the ftp service to clear the lock.

I fired up process explorer and did a search on the file in question and sure enough the ftp service has a lock on the file and it takes around 20 minutes to release the lock on its own (and sometimes longer). This lock stays around even after I disconnect the client.

Like I said this only happens about 70% of the time, the other 30% of the time it goes through just fine.

Things i have verified.

-Not a firewall issue. Server is using passive port range 8000-9000 which is allowed on the firewall. -Not a nat issue, server has a globally rout-able ip address -all recommended/required updates installed

I have 5 other servers in a very similar configuration and this is the only one i have problems with.


If you are using an Antivirus scanner and trying to transfer large files it may be locking the file. You may want to see if you can exclude that folder from the scan.


Can you check the FTP logfile and see the status for the one on which you disconnected the client. Check the status code and compare it with the ones here. Let us know what you find.

If you say it happens 70% of the time that means you should be able to reproduce the issue as well. What is the FTP client you are using, try coreftp. Try using FTP using command prompt and see if the issue still happens.

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