When using Dreamweaver CS6 you may see the error below (or similar) - If so, read on ...

Your FTP programme has exceeded the maxiumum number (3) of concurrent connections.

Number of concurrent connections

When Dreamweaver connects to a webserver for the purpose of FTP it can do so by using MORE than one connection at a time. It does this to speed up file transfers (a bit like using all three lanes and three lorries to ship goods on a motorway, instead of just one lorry on one lane).

Dreamweaver CS6 has a setting in its FTP profile that allows minimal number of conections to be used. Just DONT put a tick in the box that says Use FTP Performance Optimization. This limits the number of concurrent connections to 3.

Thats right ... The minimum number of connections Dreamweaver CS6 uses is THREE and not ONE like you might suppose.

"Three connections" is fine so long as the hosting company supports multiple FTP connections; and certainly most (including Calco) do support at least 3 simultaneous connections.

The Number of Concurrent FTP Connections Problem

Sadly file tranfer is not a perfect process and if a file doesnt transfer perfectly, the FTP programme on the SERVER tells the sender to RETRY (its seen in the logs as the command RETR.) Our curent working theory is that ... If the server issues more than three RETR commands, it seems** to cause confusion between Dreamweaver CS6 and the FTP software on the server causing error messages like :-

Your FTP programme has exceeded the maxiumum number (3) of concurrent connections.

This means any subsequent files will also generate errors until the FTP channel is RESET and the count to three begins again. Unfortunately the files DENIED transfer during the lock-out period where the number of connections was exceeded ... will NOT have been transferred and its up to the user to figure out which files were sent and which were not! **Please note that the above reason for the limit being breached is only our own in-house working theory and not a hard and no a hard and fast fact! The error however is very real.

How to fix the Dreamweaver FTP problem

WAIVER : Please do not try this at home unless you "know what you are doing" and you accept full responsibility for your own actions. Calco UK accept absolutely no responsibility if you do try this and it causes your PC to malfunction

You will be changing a setting in the WIndows Registry - so back it up (i.e. export a working copy) before starting.

1. Go to RUN, type regedit and press enter

2. Go to HKEY_CURRENT_USER ->Software->Adobe->Dreamweaver CS6->Site Preferences -> CURL_MULTI_FILES_LIMIT

3 Then Double click on CURL_MULTI_FILES_LIMIT, set the value to 1.

This will reduce Dreamweaver's maximum allowed number of simultaneous file transfers, to prevent any further upload issues.


Finally ... we use this method on many of our servers and it works just as fast as the "default" setting shipped with Dreamweaver CS6. JUST REMEMBER you have made this change to ALL your FTP profiles within Dreamweaver. You will need to UNDO it if you intend to go back to multi-threaded FTP.


Refs and Tags : Dreamweaver CS6 has problems on some FTP servers because of the concurrent connections limit.

Where is the FTP profiles Setting in Dreamweaver


Double-click the Site you want to change

Go to SERVERS and double-click the server you want to change

Go to MORE OPTIONS and UNTICK the Use FTP Performance Optimization. Press SAVE!

This reduces the number of concurrent connections to THREE.


Help Files

... or you could just use Filezilla and set the number of connections to 1 or 2.

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