I installed tor browser bundle for windows on Windows 7, 32 bit. When I start the tor browser, in 80% of the cases, I get an error with "Could not connect to tor control port". I tried with disabled antivirus and disabled firewall, but that does not help. Because sometimes I can connect, it is likely to be a timing issue. I used tor browser on the same laptop for years without problems. With version 6 the problems began. Any ideas to solve my problem?
UPDATE 2018: This appears to be a popular question so I edited my answer. I put all the solutions I could think of at the beginning of this post.
You must have made sure your firewall etc. are allowing access to 127.0.0.1:9150 and 127.0.0.1:9151 which are Tor's SOCKS and control ports. I assume you haven't modified your torrrc file. By the way, I also have 32-bit Windows 7.
Try doing strange things with tor.exe, like starting two different versions (or two copies of the same version) of the program at the same time suddenly terminating the TBB process tree and running it again, disconnecting (or switching) the network while Tor Launcher is loading, use Sysinternals Process Explorer or some other utility to suspend tor.exe, forcably closing the TCP/IP connections tor makes, click Run as Administrator before launching TBB, maybe even log out of the system while Tor Launcher is loading (and failing)... You never know which one will fix the problem. Execution order is not predictable.
But don't change Firefox, proxy or pluggable transport settings. That won't help.
As a last resort, delete the Browser\TorBrowser\Data folder and try reinstalling Tor Browser. Then start it again, choose network settings that appear on the screen and wait about 5 minutes while it connects to the Tor Network. Then "Welcome To Tor Browser" should display in the Tor Browser window.
If you have bookmarks, preferences or other stuff that you want to backup, maybe you should use FEBE from Firefox Add-ons. It will work for now (until Firefox 59 ESR comes to Tor Browser). This Mozilla Support page shows you where your things are stored on your computer.
I ran into this question (once again) two days ago after I was also getting the same error the OP got (except this time in 100% of the cases).
I tested Tor Browser versions 7.5 and 6.0.5 on Windows 32-bit and they both had this problem. After I got "Could not connect to Tor control port", they both proceeded to state "Waiting for Tor to start...". It can't detect the Tor process (why not I wonder?), so there are zero messages in the Tor log.
There appears to be a connection to a relay node but it's state is ESTABLISHED and not LISTENING. The main firefox process is waiting for Tor so the whole thing is stuck.
Standalone Tor works normally. Then I tried to run 6.0.5 while 7.5 is stuck and then I get the same problem as described in this question (The picture and the second paragraph). If I close 7.5, 6.0.5 finally opens the Tor Network settings. I then connect directly to the Tor network, it is connecting slowly... and finally loads. When I closed 6.0.5 and attempted to start 7.5, now it starts.
The Tor Project developers do a great job in testing TBB for the real world, but occasionally, no matter how streamlined the error detection system of a program is, some external conditions will still slip past it and cause problems such as yours and mine. A random error condition can be solved by doing random things such as those I have described above.
Keep that in mind the next time you have some obscure software problem.
The issue is the one I describe here. If I get a more precise solution, I shall update the comment.
I have managed to fix this issue by disabling Windows Firewall, for all 3 profiles - "Private", "Work", "Domain".
Those of us who use a third-party firewall forget to disable the native Windows Firewall which continues to run side-by-side with the third-party firewall.
So, check for Windows Firewall to be disabled even if you have already installed another Firewall.
To open the Windows Firewall settings, press on your keyboard "WIN + R" to open the "Run" window, then type "wf.msc" and press ENTER. (wf.msc = windows firewall microsoft console)
This issue with Tor happens because all other non-Microsoft firewalls usually ask the user to accept/deny unknown connections, but Windows Firewall sometimes decides instead of you to deny some connections, without even asking, so that was preventing the Tor Browser from connecting to the Tor control port in my case.
so, I have installed a third-party firewall instead of Windows Firewall and disabled Windows Firewall and now Tor works fine.