diff --git a/src/storage/GridFile.test.ts b/src/storage/GridFile.test.ts
index 9da2abe9ef..503277b918 100644
--- a/src/storage/GridFile.test.ts
+++ b/src/storage/GridFile.test.ts
@@ -37,6 +37,28 @@ describe('validateFile()', () => {
         cell_dependency: undefined,
       })
     ).not.toBe(null);
+
+    const result = validateFile({
+      ...v1File,
+      borders: [
+        { x: 0, y: 0, horizontal: { type: 0 }, vertical: { type: 0 } },
+        { x: 1, y: 1, horizontal: { type: 1 } },
+        { x: 2, y: 2, horizontal: { type: 2 } },
+        { x: 3, y: 3, horizontal: { type: 3 } },
+        { x: 4, y: 4, horizontal: { type: 4 } },
+        { x: 5, y: 5, horizontal: { type: 5 } },
+        { x: 6, y: 6, horizontal: {} },
+      ],
+    });
+
+    expect(result).toHaveProperty('borders[0].horizontal.type', 'line1');
+    expect(result).toHaveProperty('borders[0].vertical.type', 'line1');
+    expect(result).toHaveProperty('borders[1].horizontal.type', 'line2');
+    expect(result).toHaveProperty('borders[2].horizontal.type', 'line3');
+    expect(result).toHaveProperty('borders[3].horizontal.type', 'dotted');
+    expect(result).toHaveProperty('borders[4].horizontal.type', 'dashed');
+    expect(result).toHaveProperty('borders[5].horizontal.type', 'double');
+    expect(result).toHaveProperty('borders[6].horizontal', {});
   });
 
   test('Upgrades a valid file from v1 to v1.1', () => {
diff --git a/src/storage/GridFile.ts b/src/storage/GridFile.ts
index a20c2c1b9e..775d3aa477 100644
--- a/src/storage/GridFile.ts
+++ b/src/storage/GridFile.ts
@@ -99,6 +99,28 @@ export function validateFile(jsonFile: {}): GridFile | null {
       jsonFile.cell_dependency = '';
     }
 
+    // The previous enums for borders were integers but now we use strings
+    // So we have to change them all, e.g. from "3" to "dotted"
+    // https://github.com/quadratichq/quadratic/pull/308/files#diff-fb2ecd77a7c43aa1f68a862e8866d079391f51b6ae9665059d523221fdf5256fL44-R41
+    const enumMapping = {
+      0: 'line1',
+      1: 'line2',
+      2: 'line3',
+      3: 'dotted',
+      4: 'dashed',
+      5: 'double',
+    };
+    if (jsonFile && jsonFile.borders && jsonFile.borders.length > 0) {
+      ['horizontal', 'vertical'].forEach((key) => {
+        for (let i = 0; i < jsonFile.borders.length; i++) {
+          if (jsonFile.borders[i][key] && typeof jsonFile.borders[i][key].type === 'number') {
+            const value: 0 | 1 | 2 | 3 | 4 | 5 = jsonFile.borders[i][key].type;
+            jsonFile.borders[i][key].type = enumMapping[value];
+          }
+        }
+      });
+    }
+
     return jsonFile;
   };
 
diff --git a/src/storage/useLocalFiles.ts b/src/storage/useLocalFiles.ts
index b56c1ddb5e..aba21d1257 100644
--- a/src/storage/useLocalFiles.ts
+++ b/src/storage/useLocalFiles.ts
@@ -101,7 +101,7 @@ export const useLocalFiles = (sheetController: SheetController): LocalFiles => {
       // Check if the JSON is a valid quadratic file
       const quadraticJson = validateFile(json);
       if (!quadraticJson) {
-        console.error('Failed to parse JSON as a valid Quadratic file', json);
+        console.error('Failed to parse JSON as a valid Quadratic file', json, contents);
         return false;
       }