Avoid problems that can cause drawing file corruption or data loss

Issue

The program terminates unexpectedly with one of the following error types:

• DBQSPACE
• DBTHUNK
• UNHANDLED ACCESS VIOLATION EXCEPTION
• MSTACK
• SMIO
• EREAD

Note: The preceding list of errors is not necessarily complete.

Solution

These errors are usually an indication that there is a problem with the system that could lead to data loss or corruption.
This solution provides steps and suggestions that you can use to troubleshoot these errors and minimize the risk of data loss or corruption.
Hard disk maintenance
Carry out the following hard disk maintenance on a regular basis.

• Check integrity and fix any errors.
• Keep fragmentation levels to a minimum.
• Ensure there is always enough free space on the hard disk.

System resources

• Ensure there is enough free physical RAM.
• Specify an adequate size for the system swap file and, if set dynamically, ensure there is enough free disk space for it to grow to the maximum size.

Data backup

• Ensure the Autodesk® software creates BAK files. (You set this option on the Open and Save tab of the Options dialog box; the default setting is ON.)
• Employ a backup solution to back up your data on a regular basis (at least daily).

Saving to a network server in a mixed operating system environment
If you save to a network server in a mixed operating system environment (for example, Novell® or UNIX servers), you might encounter problems with file locking that can lead to data loss or corruption. The related solution, "File Locking in mixed AutoCAD environments" discusses this issue.
ISAVEPERCENT system variable
Set the ISAVEPERCENT variable to 0. This variable determines the amount of wasted space tolerated in the drawing file.You can enter an integer from 0 to 100, inclusive, for ISAVEPERCENT; the initial value is 50. When set to the initial value, the software tolerates up to 50% of wasted space in the drawing file before doing a full save. Setting ISAVEPERCENT to 0 forces the program to do a full save (not incremental) of the drawing database each time you save.
Note: This is a precautionary measure that is only necessary while you troubleshoot the problem. After you have identified and resolved the problem, you can reset the ISAVEPERCENT variable to its original value.