confusion about "A lock is not available for <dataset>"

[duanzongran]

dear all:

Recently,I was confused about "A lock is not available for <dataset>".Indeed ,it's an error,but when I restart SAS and run the code again ,the error disappeared.How to avoid the error?

When I review my code,I guess 5 possibilities  may cause this error， right or wrong？

*1.set options compress=yes;
options compress=yes;

*2.in data step,input dataset and the output dataset have the same name;
data X;set X ;run;


*3. when using proc sort ,without out= option;
proc sort data=x;by id;run;

 Any suggestion is welcome!

[Patrick]

SAS throws this error if a different process locks a table (the SAS file). In your case though the tables are in WORK and that is SAS session specific (=same process).

What can lock a table even in WORK is if you have it already open in your EG session. Below option setting helps to avoid this.

For the 3 cases you mention:

Option compress will never lock a table.

In your sample code the tables are in WORK which is SAS session (process) specific and no other process (like another SAS session) gets access to this WORK directory.

[Kurt_Bremser · Accepted solution]

Another thing that can keep a file handle open is anti-virus software which immediately scans all newly created files and prevents an overwrite (or even opens exclusively).

[duanzongran]

Yes,quite so !!!!!!!!!!!!!!!!!!!!!!!!
After checking my computer ,i found the anti-virus software installed by my IT workmate very frequently scan every file I make from sas.
When I run then code on a computer without the anti-virus software , it seems everything is OK.