diff --git a/src/ioc/db/test/dbPutLinkTest.c b/src/ioc/db/test/dbPutLinkTest.c
index 31563466f..52ae41fb5 100644
--- a/src/ioc/db/test/dbPutLinkTest.c
+++ b/src/ioc/db/test/dbPutLinkTest.c
@@ -482,9 +482,8 @@ static void testLinkFail(void)
     /* INST_IO doesn't accept empty string */
     testdbPutFieldFail(S_dbLib_badField, "rINST_IO.INP", DBR_STRING, "");
 
-    /* INST_IO accepts invalid input as empty string */
-    testdbPutFieldOk("rINST_IO.INP", DBR_STRING, "abc");
-    testdbGetFieldEqual("rINST_IO.INP", DBR_STRING, "@");
+    /* INST_IO doesn't accept empty string */
+    testdbPutFieldFail(S_dbLib_badField, "rINST_IO.INP", DBR_STRING, "abc");
 
     /* syntax errors */
     testdbPutFieldFail(S_dbLib_badField, "rVME_IO.INP", DBR_STRING, "#S201 C200 @another VME_IO");
@@ -505,7 +504,7 @@ static void testLinkFail(void)
 
 MAIN(dbPutLinkTest)
 {
-    testPlan(245);
+    testPlan(244);
     testLinkParse();
     testLinkFailParse();
     testCADBSet();
diff --git a/src/ioc/dbStatic/dbStaticLib.c b/src/ioc/dbStatic/dbStaticLib.c
index ca7dfff83..ac4276e5d 100644
--- a/src/ioc/dbStatic/dbStaticLib.c
+++ b/src/ioc/dbStatic/dbStaticLib.c
@@ -2092,9 +2092,6 @@ long dbCanSetLink(DBLINK *plink, dbLinkInfo *pinfo, devSup *devsup)
     case PV_LINK:
         if(link_type==CONSTANT || link_type==PV_LINK)
             return 0;
-        else if(link_type==INST_IO && pinfo->target[0]!='\0')
-            /* for compatibility.  Invalid non-empty INST_IO is treated as empty string */
-            return 0;
     default:
         free(pinfo->target);
         pinfo->target = NULL;
@@ -2224,14 +2221,6 @@ long dbSetLink(DBLINK *plink, dbLinkInfo *pinfo, devSup *devsup)
         dbFreeLinkContents(plink);
         dbSetLinkHW(plink, pinfo);
 
-    } else if(link_type==INST_IO && (pinfo->ltype==CONSTANT || pinfo->ltype==PV_LINK) && pinfo->target[0]!='\0') {
-        /* for compatibility.  Invalid non-empty INST_IO is treated as empty string */
-        pinfo->target[0] = '\0';
-        pinfo->ltype = INST_IO;
-
-        dbFreeLinkContents(plink);
-        dbSetLinkHW(plink, pinfo);
-
     } else
         goto fail;