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29 July 2005
The Autosave Mystery          
There seems to be a lot of confusion and misinformation out there regarding the operation of AutoCAD's automatic save function. First and foremost, it is not a replacement for the QSAVE command. AutoCAD's automatic save simply writes a copy of the current drawing to disk every so often, and when you shutdown AutoCAD normally, those file(s) are deleted.

Here is more or less a rundown of what occurs:

  • As soon as a new drawing is modified (in other words, when DBMOD does not equal 0), a timer starts.
  • When this timer reaches the value of the SAVETIME system variable, the automatic save function fires, an autosave file is created, and the timer is reset.
  • The autosave file is created in the directory defined by the SAVEFILEPATH system variable. File naming syntax is described below.
  • The timer is also reset anytime QSAVE, SAVE, or SAVEAS is executed.


Naming of the autosave file
The autosave file is named using this syntax:
drawing name_AutoCAD session number_MDE Window number_random number.sv$
...where

  • drawing name = the original drawing name.
  • AutoCAD session number = a number generated sequentially regarding concurrent sessions of AutoCAD.
  • MDE Window number = a number generated sequentially regarding concurrent open drawings in each session.
  • random number = a random number
  • .sv$ = this is always the file extension for autosave files.

A typical autosave file name might be: siteplan_2_4_2810.sv$

Sometimes AutoCAD may 'crash', but the autosave files are deleted anyway. I have seen this after AutoCAD generates a fatal error and you get the dialog that says "AutoCAD can not continue, do you want to save changes?" - in this case, AutoCAD is giving you a chance to save your changes (although I recommend saying NO in this case - but I'll save that story for another day...) Anyway, in the above case, the autosave file(s) will be deleted.

Autosave files can be used by renaming them from .SV$ to .DWG

AutoCAD 2006 users get a new GUI called the "Drawing Recovery Manager" - now you don't have to search for and manually rename files anymore.

One more TIP: If you want to RETAIN all autosave files regardless of whether you crash or not. Set up a directory on your server with WRITE rights, but without DELETE rights. Use this as your SAVEFILEPATH. The autosave files will get written to this directory, but will not be deleted. Be sure to log in as a user with delete rights ever so often and clean out this directory.

Update:Always make sure ISAVEPERCENT is set to zero (0).

Moral of the story: QSAVE OFTEN

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PermaLink       Posted 7/29/2005 09:02:00 PM     
11 COMMENTS!


Comment from: Anonymous Anonymous
Date: October 10, 2005 at 8:47:00 AM CDT  

Why "Always make sure ISAVEPERCENT is set to zero (0)." ??


Comment from: Blogger R.K. McSwain
Date: October 13, 2005 at 9:19:00 AM CDT  

Otherwise, AutoCAD only writes the changed portion of the database to disk. There have been numerous accounts of a non-zero setting causing all sorts of drawing corruption problems.


Comment from: Anonymous Anonymous
Date: November 8, 2005 at 8:31:00 AM CST  

OK, if QSAVE is the only answer to saving files, is there a way to program the QSAVE command on a timer to save automatically? I also use the autosave directory to keep track of what I've worked on and have been frustrated when files are not there. Is there another way to review files that have been worked on in the past?


Comment from: Anonymous Adam Kimber
Date: May 9, 2007 at 9:06:00 AM CDT  

Making the save directory for autosaves read only is a stroke of genius. It allows recovery of lost work after a power cut etc.

Whilst QSAVEing regularly is the best option sometimes you forget and this is the lifeline for those occasions.

Thank you for this suggestion,


Comment from: Blogger R.K. McSwain
Date: May 9, 2007 at 9:27:00 AM CDT  

Adam,
If you have a power outage, the autosave files will be retained regardless if they are in a 'delete-protected' directory or not.

But this does protect against autosave drawing loss in other cases.


Comment from: Anonymous Anonymous
Date: May 10, 2007 at 6:19:00 AM CDT  

When I change the properties of the autosave folder to remove the delete rights, autocad comes up with the error "unable to save to drawing....drawing saved to..."

How do I avoid this?

ISAVEPERCENT is set to 0, and I'm using Autocad 2008 full version.

Many thanks,

TT


Comment from: Blogger R.K. McSwain
Date: May 10, 2007 at 7:12:00 AM CDT  

Check the rights again. You only want to remove "delete" rights. It still needs "write" access.


Comment from: Anonymous Anonymous
Date: May 10, 2007 at 7:40:00 AM CDT  

I've only removed the 'delete' and 'delete subfolders and files' rights only, but it still comes up with that error.

Any help is greatly appreciated,

TT


Comment from: Anonymous CSmith
Date: March 26, 2008 at 1:01:00 PM CDT  

I've set my temp folder to allow deletion of files, which works if I try to manually delete them. But when AutoCAD closes the drawing the autosave files are deleted. Any ideas?


Comment from: Anonymous Anonymous
Date: May 23, 2008 at 10:10:00 AM CDT  

I get warning message that says "unable to save to location... saved as a *.tmp file" everytime AutoCAD autosaves. Is there a way to stop AutoCAD from displaying this warning message?


Comment from: Blogger arjuna
Date: June 2, 2008 at 9:57:00 AM CDT  

very easy.

Just make each 10 min an automatic copy of your backupfiles. Autocad does not touch that folder. You can automatically delete the content of your folder in the weekend.

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