diff --git a/ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js b/ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js
index 3ba889c393..709d3414c3 100644
--- a/ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js
+++ b/ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js
@@ -854,12 +854,18 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
       return true;
     }
 
+
     //! Documented elsewhere in this file.
     exportFile(name){
       const sah = this.#mapFilenameToSAH.get(name) || toss("File not found:",name);
       const n = sah.getSize() - HEADER_OFFSET_DATA;
-      const b = new Uint8Array(n>=0 ? n : 0);
-      if(n>0) sah.read(b, {at: HEADER_OFFSET_DATA});
+      const b = new Uint8Array(n>0 ? n : 0);
+      if(n>0){
+        const nRead = sah.read(b, {at: HEADER_OFFSET_DATA});
+        if(nRead != n){
+          toss("Expected to read "+n+" bytes but read "+nRead+".");
+        }
+      }
       return b;
     }
 
@@ -879,8 +885,13 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
       const sah = this.#mapFilenameToSAH.get(name)
             || this.nextAvailableSAH()
             || toss("No available handles to import to.");
-      sah.write(bytes, {at: HEADER_OFFSET_DATA});
-      this.setAssociatedPath(sah, name, capi.SQLITE_OPEN_MAIN_DB);
+      const nWrote = sah.write(bytes, {at: HEADER_OFFSET_DATA});
+      if(nWrote != n){
+        this.setAssociatedPath(sah, '', 0);
+        toss("Expected to write "+n+" bytes but wrote "+nWrote+".");
+      }else{
+        this.setAssociatedPath(sah, name, capi.SQLITE_OPEN_MAIN_DB);
+      }
     }
 
   }/*class OpfsSAHPool*/;
@@ -1087,6 +1098,9 @@ globalThis.sqlite3ApiBootstrap.initializers.push(function(sqlite3){
      automatically clean up any non-database files so importing them
      is pointless.
 
+     On a write error, the handle is removed from the pool and made
+     available for re-use.
+
      - [async] number reduceCapacity(n)
 
      Removes up to `n` entries from the pool, with the caveat that it can
diff --git a/manifest b/manifest
index 76f5f962e1..8a308da5a1 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Fix\sa\sbug\sin\sthe\sjsonLookup()\sroutine\sused\sto\ssearch\sJSON.\s\sBug\swas\nintroduced\sby\sthe\srecent\s(unreleased)\sJSON\scaching\senhancements\ncheck-in\s[a4c1af616e672a0d]\smerged\sinto\strunk\sat\s[df099ad713011b67].
-D 2023-08-04T13:19:11.464
+C In\sthe\sopfs-sahpool\sVFS's\simportDb()\sand\sexportFile()\smethods,\sthrow\sif\sthe\sactually-wrote/read\samounts\sdiffer\sfrom\sthe\sexpected-to-write/read\samounts,\sper\sfeedback\sin\s[forum:a4122e986f|forum\spost\sa4122e986f].
+D 2023-08-04T16:01:55.085
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -507,7 +507,7 @@ F ext/wasm/api/sqlite3-api-worker1.js 9f32af64df1a031071912eea7a201557fe39b17386
 F ext/wasm/api/sqlite3-license-version-header.js 0c807a421f0187e778dc1078f10d2994b915123c1223fe752b60afdcd1263f89
 F ext/wasm/api/sqlite3-opfs-async-proxy.js 8cf8a897726f14071fae6be6648125162b256dfb4f96555b865dbb7a6b65e379
 F ext/wasm/api/sqlite3-v-helper.js 7daa0eab0a513a25b05e9abae7b5beaaa39209b3ed12f86aeae9ef8d2719ed25
-F ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js 54cee22aacadb9dfaea438d72ac0882249d028c37903208d48c52871290ceff7
+F ext/wasm/api/sqlite3-vfs-opfs-sahpool.c-pp.js abb69b5e008961026bf5ff433d7116cb046359af92a5daf73208af2e7ac80ae7
 F ext/wasm/api/sqlite3-vfs-opfs.c-pp.js e7a690e0e78ff4d563f2eca468f91db69f001ff4b79c6d2304cbb6f62dca437d
 F ext/wasm/api/sqlite3-wasm.c 8867f1d41c112fb4a2cfe22ff224eccaf309fcdea266cee0ec554f85db72ef0f
 F ext/wasm/api/sqlite3-worker1-promiser.c-pp.js bc06df0d599e625bde6a10a394e326dc68da9ff07fa5404354580f81566e591f
@@ -2049,8 +2049,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b7de399c277394a6a3bbf253d4177aa82753271e5087b98b2c2268f629a7dfdd
-R 0023494055da434d093283e3467ed659
-U drh
-Z fcef72d2f53678066563a17e3c8f660b
+P ba7a66db13b28da0b41f03be825a593608474a5ebda89e12d58d89db709b8f65
+R f2c78f56dfb337758355d58b9337ecba
+U stephan
+Z 00aafcc21ac118e76e1aadfe455b796f
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index e5cb58fc65..17fc756294 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ba7a66db13b28da0b41f03be825a593608474a5ebda89e12d58d89db709b8f65
\ No newline at end of file
+a617ebf4e5d1af1b5b15e9782ad111399caaa3ea7b99bb0c8691c8b4283b6d6e
\ No newline at end of file