Fiddler memory usage is troubling

[Damien]

I've been using Fiddler for over a decade, every day, all day. I can't say enough about how much I rely on the program.

Recently I've been working at a job where I was given a Macbook, on which I run a Windows 7 Virtual Machine for the sole purpose of using fiddler.

The VM has x64 Windows 7 Ultimate, with 4GB of RAM allocated to it, and 2 CPU cores. There's nothing out of the ordinary with the VM as far as I can tell. 

When I start Fiddler 4 (latest version, 4.4.9.9), at first it has a memory footprint of 25MB. It stays at 25MB while there is no traffic going to Fiddler.

Once I start sending traffic through Fiddler, the memory footprint quickly climbs to 1GB. Not satisfied with 1GB, Fiddler quickly passes that mark and climbs to 1.5GB, 2GB, and after just about 30 minutes, Fiddler is consuming 3.3GB of RAM!!   

Now, I'm very aware of setting "Keep 100 sessions", and I do have it set at 100 sessions, but even with this set, Fiddler doesn't seem to care. It wants ALL OF MY RAM. I'm sure if I had given the VM more than 4GB, it would be happy to consume all of it.

I also set Fiddler to not capture traffic (turn off capturing in the lower-left corner of the Fiddler ui), so any net traffic originating inside the VM doesn't go through fiddler. I'm using the "allow remote computers to connect" feature of fiddler to allow my OSX host OS to send traffic through fiddler. I can only think that using this option somehow bypasses the normal garbage collection, and I end up with a bloated Fiddler taking up all of my RAM.

I've also tried removing the Fiddlerscripts I created, but that has no effect, Fiddler still eats all my RAM.

I've tried everything I can think of, turning on/off Stream, Decode, and other Fiddler options, with no effect on the memory bloat.

It wouldn't bother me if Fiddler performed well anyway, but it does not, it slows down to a crawl and eventually I can't get any work done like this.

I have to restart fiddler constantly, reboot the VM, and my development process has been affected quite negatively since using this setup.

I've also tried Fiddler for OSX, but it doesn't seem ready for prime-time.

[EricLaw]

Fiddler for OSX is indeed "not ready for prime time" but no, capturing remote traffic will not impact G/C in general.

Step 1 is to upgrade to Fiddler 4.5 so we're all on the same page.

Step 2 is to reproduce the problem.

Step 3 is to type !memory in the QuickExec box below the Web Sessions list.

Step 4 is to minimize Fiddler, restore it, and repeat step #3.

Step 5 is to reply to this thread with contents of Fiddler's LOG tab. You can attach as a text file.

Thanks!

[Damien]

I took a look at the Programs and Features in the control panel in the VM I was using, and it has some unusual things installed that made me think this VM was the problem and not Fiddler. I got the VM from someone at work, not sure what they were using it for, so...  

I installed a new Win 7 VM, installed fiddler, and the new VM seems to be working very well, no memory problems at all. Fiddler is staying around 50MB of RAM, which is amazing.  Thanks for your help, and I'm sorry to have jumped to blame fiddler for the excessive memory usage.