10 July 2007
Tracking down why that application is slow          

Do you have an application such as AutoCAD that is displaying any of the following symptoms?

  • Starting up slower than normal?
  • Running slower than normal?
  • Long delays when you try to run a particular function, like save, open, or plot?
If you have already ruled out typical suspects such as a virus, spyware, malware, hardware limitations, etc., then there is a good chance that maybe the application is simply looking for something that isn't there.

Windows and windows applications like to search for things for what seems like en eternity. How can you find out what is going on behind the scenes?

I've been using FileMon for years to view file activity in real-time. Many times you can spot a missing file or path that your application is looking for.

FileMon was originally developed and released by Winternals Software, available on their website, However, in July 2006, Microsoft acquired Winternals Software and now FileMon and other similar tools are available at

FileMon (and most of the other "sysinternals" tools) are simple yet powerful, require no installation, very small in size, and best of all, free.

After you download the program (a tiny 280k download), unzip the contents. You can unzip the contents to a flash drive if you want it to be portable or you can simply unzip it into a local directory like C:\Program Files\FileMon . You will end up with 3 files. An executable, a help file, and the EULA.

Run the executable (filemon.exe) to get started. The first thing you will see is the "FileMon Filter" dialog. Here you can include, exclude, and highlight certain strings. For now, don't change anything, just press OK.

Now, depending on what applications you have running, you will see a variety of file activity going on. Even if it seems like your computer is idle, there may still be quite a lot of file activity happening. Things like virus checkers, media players, email applications, etc. may be working away even though they seem idle. Now that you have seen what this tool does, how can you use it to find out what is slowing you down?

Let's say your AutoCAD takes a long time to start up, and let's assume that the problem lies completely within AutoCAD to start with. So let's filter out all other file activity. Press Ctrl+L to open the filter dialog again. In the INCLUDE field, enter *acad*. This will instruct FileMon to ignore everything unless it contains "acad". If you have dual monitors, place FileMon on the opposite monitor from where AutoCAD opens. If you have a single monitor, position and size FileMon so that you can see the AutoCAD command line and then click the Options menu in FileMon and select "Always on Top". This will keep FileMon visible even when AutoCAD takes focus.

Now start up AutoCAD. You will see a line after line start scrolling by, probably faster than you can read it. Pay attention though, and when AutoCAD seems to freeze up, take a look at the FileMon screen and look at the last few lines, particularly the Path and Result columns. Is AutoCAD looking for a drive letter or network path that does not exist? Maybe it's looking for an add-on file that doesn't exist any more. If you don't see anything obvious, you may have to go back to the FileMon filter and remove the *acad* filter. Press the Defaults button to allow it to monitor ALL file activity. Maybe another application is slowing down AutoCAD by running some sort of process during AutoCAD startup.

FileMon has helped diagnose a problem where a particular DWG file just would not load in AutoCAD. It looked like AutoCAD was just locked up after loading about 20% of this drawing. FileMon revealed that the virus checker was busy scanning four, 18MB .SID files that were referenced in the DWG file. In another case, AutoCAD was taking almost a minute to open the MTEXT editor, but only the first time it was initiated. After using FileMon, it was determined that AutoCAD was finding over 300 fonts in the various search paths, and AutoCAD was reading each font once, the first time the MTEXT editor was launched.

Hopefully, you can use this tool to help diagnose a problem that you are having.

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PermaLink       Posted 7/10/2007 05:25:00 AM     

Comment from: Blogger Dave Dixon
Date: July 10, 2007 at 12:19:00 PM CDT  

Very nice. I'll have to download this one. Thanks.

Comment from: Blogger John
Date: July 10, 2007 at 8:36:00 PM CDT  

Very useful. Thanks R.K.

Comment from: Anonymous guictx
Date: July 25, 2007 at 2:03:00 PM CDT  

Thank you so much. I finally figured out why my AutoCAD was freezing at atartup. It got stuck on a font file.

Comment from: Anonymous Anonymous
Date: July 31, 2007 at 12:07:00 PM CDT  

thanks....font file again

Comment from: Anonymous Anonymous
Date: March 20, 2008 at 12:51:00 PM CDT  

thank you very much, what a lifesaver

Comment from: Anonymous Anonymous
Date: May 12, 2008 at 2:38:00 AM CDT  

My AutoCad at startup spend a lot of time on the cryptnet.dll only if the lan cable is connected.
If is't, the program start quickly.
Can somebody tell me why?

Comment from: Anonymous Ruud
Date: August 12, 2008 at 4:03:00 AM CDT  

Excellent, sorted some extreme delays with this tool and explanation! Thanks very much!

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