Index: src/build.c
==================================================================
--- src/build.c
+++ src/build.c
@@ -146,11 +146,11 @@
     ** set for each database that is used.  Generate code to start a
     ** transaction on each used database and to verify the schema cookie
     ** on each used database.
     */
     if( pParse->cookieGoto>0 ){
-      u32 mask;
+      tAttachMask mask;
       int iDb;
       sqlite3VdbeJumpHere(v, pParse->cookieGoto-1);
       for(iDb=0, mask=1; iDb<db->nDb; mask<<=1, iDb++){
         if( (mask & pParse->cookieMask)==0 ) continue;
         sqlite3VdbeUsesBtree(v, iDb);
@@ -3442,16 +3442,16 @@
     if( v==0 ) return;  /* This only happens if there was a prior error */
     pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
   }
   if( iDb>=0 ){
     sqlite3 *db = pToplevel->db;
-    int mask;
+    tAttachMask mask;
 
     assert( iDb<db->nDb );
     assert( db->aDb[iDb].pBt!=0 || iDb==1 );
     assert( iDb<SQLITE_MAX_ATTACHED+2 );
-    mask = 1<<iDb;
+    mask = ((tAttachMask)1)<<iDb;
     if( (pToplevel->cookieMask & mask)==0 ){
       pToplevel->cookieMask |= mask;
       pToplevel->cookieValue[iDb] = db->aDb[iDb].pSchema->schema_cookie;
       if( !OMIT_TEMPDB && iDb==1 ){
         sqlite3OpenTempDatabase(pToplevel);
@@ -3474,11 +3474,11 @@
 ** necessary to undo a write and the checkpoint should not be set.
 */
 void sqlite3BeginWriteOperation(Parse *pParse, int setStatement, int iDb){
   Parse *pToplevel = sqlite3ParseToplevel(pParse);
   sqlite3CodeVerifySchema(pParse, iDb);
-  pToplevel->writeMask |= 1<<iDb;
+  pToplevel->writeMask |= ((tAttachMask)1)<<iDb;
   pToplevel->isMultiWrite |= setStatement;
 }
 
 /*
 ** Indicate that the statement currently under construction might write

Index: src/main.c
==================================================================
--- src/main.c
+++ src/main.c
@@ -1721,12 +1721,12 @@
 # error SQLITE_MAX_VDBE_OP must be at least 40
 #endif
 #if SQLITE_MAX_FUNCTION_ARG<0 || SQLITE_MAX_FUNCTION_ARG>1000
 # error SQLITE_MAX_FUNCTION_ARG must be between 0 and 1000
 #endif
-#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>30
-# error SQLITE_MAX_ATTACHED must be between 0 and 30
+#if SQLITE_MAX_ATTACHED<0 || SQLITE_MAX_ATTACHED>62
+# error SQLITE_MAX_ATTACHED must be between 0 and 62
 #endif
 #if SQLITE_MAX_LIKE_PATTERN_LENGTH<1
 # error SQLITE_MAX_LIKE_PATTERN_LENGTH must be at least 1
 #endif
 #if SQLITE_MAX_COLUMN>32767

Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -2123,10 +2123,17 @@
   SubProgram *pProgram;   /* Program implementing pTrigger/orconf */
   u32 aColmask[2];        /* Masks of old.*, new.* columns accessed */
   TriggerPrg *pNext;      /* Next entry in Parse.pTriggerPrg list */
 };
 
+/* Datatype for the bitmask of all attached databases */
+#if SQLITE_MAX_ATTACHED>30
+  typedef sqlite3_uint64 tAttachMask;
+#else
+  typedef unsigned int tAttachMask;
+#endif
+
 /*
 ** An SQL parser context.  A copy of this structure is passed through
 ** the parser and down into all the parser action routine in order to
 ** carry around information that is global to the entire parse.
 **
@@ -2171,12 +2178,12 @@
     u8 tempReg;           /* iReg is a temp register that needs to be freed */
     int iLevel;           /* Nesting level */
     int iReg;             /* Reg with value of this column. 0 means none. */
     int lru;              /* Least recently used entry has the smallest value */
   } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
-  u32 writeMask;       /* Start a write transaction on these databases */
-  u32 cookieMask;      /* Bitmask of schema verified databases */
+  tAttachMask writeMask;  /* Start a write transaction on these databases */
+  tAttachMask cookieMask; /* Bitmask of schema verified databases */
   u8 isMultiWrite;     /* True if statement may affect/insert multiple rows */
   u8 mayAbort;         /* True if statement may throw an ABORT exception */
   int cookieGoto;      /* Address of OP_Goto to cookie verifier subroutine */
   int cookieValue[SQLITE_MAX_ATTACHED+2];  /* Values of cookies to verify */
 #ifndef SQLITE_OMIT_SHARED_CACHE

Index: src/vdbeInt.h
==================================================================
--- src/vdbeInt.h
+++ src/vdbeInt.h
@@ -300,11 +300,11 @@
   u8 inVtabMethod;        /* See comments above */
   u8 usesStmtJournal;     /* True if uses a statement journal */
   u8 readOnly;            /* True for read-only statements */
   u8 isPrepareV2;         /* True if prepared with prepare_v2() */
   int nChange;            /* Number of db changes made since last reset */
-  int btreeMask;          /* Bitmask of db->aDb[] entries referenced */
+  tAttachMask btreeMask;  /* Bitmask of db->aDb[] entries referenced */
   int iStatement;         /* Statement number (or 0 if has not opened stmt) */
   int aCounter[3];        /* Counters used by sqlite3_stmt_status() */
   BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
 #ifndef SQLITE_OMIT_TRACE
   i64 startTime;          /* Time when query started - used for profiling */

Index: src/vdbeaux.c
==================================================================
--- src/vdbeaux.c
+++ src/vdbeaux.c
@@ -948,12 +948,12 @@
 ** will be used so that it can acquire mutexes on them all in sorted
 ** order (via sqlite3VdbeMutexArrayEnter().  Mutexes are acquired
 ** in order (and released in reverse order) to avoid deadlocks.
 */
 void sqlite3VdbeUsesBtree(Vdbe *p, int i){
-  int mask;
-  assert( i>=0 && i<p->db->nDb && i<sizeof(u32)*8 );
+  tAttachMask mask;
+  assert( i>=0 && i<p->db->nDb && i<sizeof(tAttachMask)*8 );
   assert( i<(int)sizeof(p->btreeMask)*8 );
   mask = ((u32)1)<<i;
   if( (p->btreeMask & mask)==0 ){
     p->btreeMask |= mask;
     sqlite3BtreeMutexArrayInsert(&p->aMutex, p->db->aDb[i].pBt);

Index: test/attach.test
==================================================================
--- test/attach.test
+++ test/attach.test
@@ -150,18 +150,20 @@
   catchsql {
     ATTACH 'test.db' as db10;
     ATTACH 'test.db' as db11;
   }
 } {0 {}}
-do_test attach-1.19 {
-  catchsql {
-    ATTACH 'test.db' as db12;
-  }
-} {1 {too many attached databases - max 10}}
-do_test attach-1.19.1 {
-  db errorcode
-} {1}
+if {$SQLITE_MAX_ATTACHED==10} {
+  do_test attach-1.19 {
+    catchsql {
+      ATTACH 'test.db' as db12;
+    }
+  } {1 {too many attached databases - max 10}}
+  do_test attach-1.19.1 {
+    db errorcode
+  } {1}
+}
 do_test attach-1.20.1 {
   execsql {
     DETACH db5;
   }
 } {}
@@ -177,18 +179,20 @@
 do_test attach-1.21 {
   catchsql {
     ATTACH 'test.db' as db12;
   }
 } {0 {}}
-do_test attach-1.22 {
-  catchsql {
-    ATTACH 'test.db' as db13;
-  }
-} {1 {too many attached databases - max 10}}
-do_test attach-1.22.1 {
-  db errorcode
-} {1}
+if {$SQLITE_MAX_ATTACHED==10} {
+  do_test attach-1.22 {
+    catchsql {
+      ATTACH 'test.db' as db13;
+    }
+  } {1 {too many attached databases - max 10}}
+  do_test attach-1.22.1 {
+    db errorcode
+  } {1}
+}
 do_test attach-1.23 {
   catchsql {
     DETACH "db14";
   }
 } {1 {no such database: db14}}