# Front end typing lag

Under Windows 7 I frequently get serious keyboard lag. My home machine (Windows XP) NEVER lags. I was able to improve things somewhat by running Mathematica as Administrator, but this only went so far. The machine is very powerful, has tons of memory.

The symptom is that any keypress or mouse click takes a second or two before anything happens. It is EXTREMELY annoying. You click the left arrow key, wait, click arrow key again, wait, click arrow key again, wait,... eventually you get to the place you need to be. If you hold the arrow key down, the system hangs then 5 seconds later the cursor appears 4 words over.

Other applications running on the same computer at the same time show no effect. Word, Excel, even total memory hogs like Adobe Illustrator run and respond immediately to keystrokes. Only Mathematica is displaying this lag.

I guess I can use a assembly language debugger to find out where the loop is that is lagging it out, but I am hoping somebody can save me the agony of doing this.

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I know there is a combination of keys that you can press while launching Mathematica so that its installation resets to factory defaults. I think it is Ctrl+Shift. Do it using a limited account and if it works it will ask you for administrator credentials. –  Hector Nov 12 '13 at 5:52
Are you using something like Comodo that might be sandboxing Mathematica? –  Hector Nov 12 '13 at 5:54
@Hector To perform a clean start on Windows, start Mathematica while holding down the Ctrl and Shift keys. Keep the keys held down until one of Mathematica‘s screens appears. If this does not seem to work, you can perform a clean start manually by deleting the Base Directory and User Base Directory on the computer. from support.wolfram.com/kb/3274 –  belisarius Nov 12 '13 at 6:32
I encountered the same problem on a Linux machine running Mathematica 7. And after a while Mathematica even crashed. –  asterix314 Nov 12 '13 at 7:13
Try switching off syntax colouring and see if that helps -- with larger notebooks it can really slow things down. You can do this in the preferences menu, appearance tab. –  Mike Honeychurch Nov 12 '13 at 7:30

I think I have figured this out. I turned off a number of Windows 7 "features" and typing became responsive. Here are the things I turned off:

Go to: Control Panel \ All Control Panel Items \ Programs and Features

Click Turn on/off Windows Features on left nav panel.

Turn off:

• Indexing Service
• Remote Differential Compression
• Windows Search

After doing this Mathematica is behaving normally. The basic problem seems to be that Mathematica is writing some file (or by side effect causing a file to be written) every time a character is typed, and the above "features" greatly slow down file access.

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Thank you, it looks like a true answer. –  Alexei Boulbitch Dec 13 '13 at 9:05