AutoCad Files Corrupted

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FontaineMax Posts 1 Registration date Thursday November 6, 2014 Status Member Last seen November 6, 2014 - Nov 6, 2014 at 10:50 AM
jaderk Posts 1 Registration date Thursday November 6, 2014 Status Member Last seen November 6, 2014 - Nov 6, 2014 at 06:23 PM
I need to recover my autocad files. Every time I try to open a .dwg file it says "drawing file is not valid".

I tried to open the .bak, but it having the same problem.
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jaderk Posts 1 Registration date Thursday November 6, 2014 Status Member Last seen November 6, 2014 2
Nov 6, 2014 at 06:23 PM
If still the drawing persists with problems, continue on to the next set of steps. These can be done in any order, but have been listed in the order that Autodesk recommends makes the most sense. The file can be checked after each step. If things appear back to normal, there is no need to continue on to the rest of the steps.
Open a blank DWG and type RECOVER at the command line. Browse to the problematic file to allow AutoCAD a chance to restore the file.
Type OVERKILL at the command line, and select all objects. Check or uncheck properties to include or ignore, then click OK.
Type DELCON at the command line, and select all objects.
Type BREP and select all objects (if there are solids or surfaces in the file)
Type -SCALELISTEDIT, then "R" for reset, then "Y" for yes.
Type FILTERS, then click on the 'delete filters' button.

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.

Open a blank DWG, and try to attach the problematic file as an XREF. If it allows you to attach the file, try next to BIND it to the current file. If that works, run the repair steps listed above.
Use the SAVEAS command to save the DWG in an older file format. Attempt to open the newly created file.
Export the file to DXF format using the DXFOUT command. Next, open a blan DWG and use the DXFIN command to import the file just created.
Restore the Layout tabs:
Right-Click one of the default layout tabs
Select 'From Template...'
Open the original file
Choose the layout tabs to restore. (It is recommended to do this one tab at a time, in case one or more layout tabs are corrupted)
Move drawing objects between model and paper space. You may find that only one drawing space is usable in your file, although your main concern is model space:
Create a new layout and if need be, create a viewport.
Use CHSPACE to move all the geometry to paper space.
Create a new drawing and use the Design Center (ADC) to move the layout from the damaged file into it.
Use CHSPACE again to move the geometry back to model space.

Restore the original layouts from the bad file using the Design Center.

Dissect the drawing. In a copy of the file, conduct a process of elimination using QSELECT to select different object types and then delete them to see if that fixes what is wrong in the file. Do PURGE All after each deletion. Eventually you should remove the problem elements and then you can choose to leave them out, copy them in again from another file, recreate them, or further troubleshoot individual items to pinpoint exactly which one is problematic. A quick start to this whole process is to delete everything in the drawing and then test it. This will quickly tell you if the issue is with a drawing object or if it is a part of the drawing database.

You also may refer to paid software DWG Viewer Tool

Source: https://dwg.recoverytoolbox.com/
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