Have Autocad 2006 network license. When working with any file Autocad crashes and shuts down. When I reopen the application, it recovers the file and works fine for 30-40 mins and the same problem re-occurs. This happens on all my 5 nodes.

Try using a different version of AutoCAD to open the drawing, such as AutoCAD 2013 vs. AutoCAD 2015 or plain AutoCAD vs. AutoCAD Architecture, etc. Try different computers if available. or try DWG Viewer Tool on website:http://www.ask.com/answers/722146801/how-to-view-corrupted-autocad-drawing?qsrc=14106

Use the autosave files to recover your work
1. Go to Tools --> Options
2. Inside Options go to the "Files" Tab (far left)
3. Inside the files tab go to: "Automatic Save File Location" and see where the autosave files are stored. (mine where stored at C:\Documents and Settings\USERNAME\Local Settings\Temp)
4. Then access that folder and try to find a file with the same file name but different extension. (The autosave files should have a either a .BAK or a .SV$ extension) (if you can't see the folder, you need to go to Tools --> folder Options --> View --> and Make sure "show hidden files and folders" is SELECTED) .
5. Check the "date modified" of those files, if the date and time makes sense according to when you had the last file crshes, there is a good chance that those files contain the information you need, so there is no need to redraw everything.
6. Change the file extension of the file you think it might be the good one from .bak or .sv$ to .dwg (to be able to change the file extension you need to be able to see it. To do that, on any folder go to Tools --> Folder Options --> View --> and make sure that "Hide extensions for known file types" is UNCHECKED)
7. Use third party software in case the guide about wasnt effective
DWG Repair Toolbox http://www.autocad.repairtoolbox.com/

AutoCAD RECOVER command?
If doesn't help, try it:
DWG Repair Kit
This professional AutoCAD DWG repair tool features a uniquely efficient data analysis core and an interface that both professionals and novices with appreciate. The program will show you how to repair DWG files online in seconds even if you have never worked with data recovery tools of any sort!
For more information: http://www.dwg.repair/

Also look here: https://social.technet.microsoft.com/Forums/en-US/fb2d8693-9551-43b7-9310-584471d60a56/autocad-files-corrupted?forum=w7itproappcompat

You can fix this problem in two ways.
First: follow these steps
- Open the Registry Editor by typing "regedit" in the Windows 8 Search charm and selecting "regedit" from the Apps section of the search results.
- Navigate to the "HKEY_LOCAL_MACHINE\Software\Autodesk\AutoCAD\R15.0\ACAD-1:405\AdLM\Type" registry key.
- Right-click on the registry key and click "Export."
- Choose a name to save the license registry key file as, along with a location where you want to save it, and then click the "Save" button.
But if it useless try the second way- DWG Fix Toolbox. http://www.autocad.fixtoolbox.com/

You may recover .dwg file with dwg corrupt file repair
Material http://www.autocad.repairtoolboxx.com could be interesting for autocad files

http://knowledge.autodesk.com/support/autocad/troubleshooting/caas/sfdcarticles/sfdcarticles/AutoCAD-2010-does-not-start.html

Issue:

When you try to start AutoCAD, you briefly see the splash screen and the program does not start.

Solution:

This behaviour can be caused by corrupted license information.
Please check if there are any errors listed in the ACD2010ENGAdlm.log file in the folder:

C:\Documents and Settings\All Users\Application Data\Autodesk\Adlm (Windows XP)

or

C:\ProgramData\Autodesk\ADLM (Windows Vista) (Please note the file name may be slightly different for localized product versions, for example for the German version the file name is ACD2010-DEUAdlm.log)
If the log file shows errors regarding the product information table file, for example "Unable to locate the Product Information Table File" or "Product Information Table file is not found", you will need to:

1. Uninstall all installed 2010 products
2. Delete the ADLM folder mentioned above, and
3. Reinstall the products

Fixya does not provide aly product or license keys for activation of any software application. We do not support software piracy because that is illegal and would eventually take you into trouble sooner or later. I would highly advice that you purchase your own genuine key for your own use.

You will need to contact Autodesk to resolve this as this cannot be solved on this forum.

Thanks for your response.

To fix the problem I redrew the componenet and deleted the offending file. I found that I could open the file with AutoCad LT but not AutoCad 2009 Mechanical.

Best regards
Trebleblank