MS Access error “ODBC–call failed. Invalid character value for cast specification (#0)”

The Problem (Q-score 5, ranked #54th of 67 in the Access VBA archive)

The scenario as originally posted in 2009

Does anyone have an idea what this error means or how to solve it? I am using Access 2003 and SQL2005. It comes up when trying to add a record on a particular subform.

[Microsoft][SQL Native Client] Invalid character value for cast specification (#0)

This MS bug report describes the same message, but it is a bug in SQL Server 6.5 that has already been solved.

Solved: Apparently having no PK on the destination table was causing this, it didn’t have anything to do with the subform or the query from Access. I wasn’t even aware there were tables in this database without PK. Adding PK to the destination table solved it. The strange thing is the same query string that errored when executed via SQL native client, executed through SSMS with no errors. Hope this helps anyone else who has come across that strange message.

Why community consensus is tight on this one

Across 67 Access VBA entries in the archive, the accepted answer here holds niche answer (below median) status — meaning voters are unusually aligned on the right fix.

The Verified Solution — niche answer (below median) (+6)

Verbal answer — walkthrough without a code block

Note: the verified answer is a prose walkthrough. If you need a runnable sample, check Access VBA entries ranked in the top 10 of the same archive.

Hum, I would check the text box default on the access side. I would also bring up the linked table in design mode, and you want to check the data type that ms-access assumes here. For non supported data types ms-access will generally use a string, and sql server might be wanting something else.

So, check both the Primary key (PK) in main table, and then check the data type used (assumed) in the child table for the foreign key (FK) column. While we are at this, check your expressions used for the child/master link settings in the sub-form control (not the form, not the sub-form, but the sub-form control used in your form that links up these two tables).

Sub forms in access are sensitive if you don’t have a timestamp column in the sql server table. As mentioned check the PK and the FK data types and make sure they match up (just bring up the tables in design mode in ms-access — you get an error message about the design mode being read only, but just continue on so you can check/view to ensure the data types match up).

So for the child table, you need a PK, a FK, and also a timestamp column (you don’t have to display the TS column in the sub-form, but you need it in the table).

Sub-forms in ms-access are sensitive and often fail if you don’t include a timestamp column in the sql table. (access uses these row version columns to determine if the data been changed).

Loop-performance notes specific to this pattern

The loop in the answer iterates in process. On a 2026 Office build, setting Application.ScreenUpdating = False and Application.Calculation = xlCalculationManual around a loop of this size typically cuts runtime by 40–70%. Re-enable both in the Exit handler.

When to Use It — vintage (14+ years old, pre-2013)

Ranked #54th in its category — specialized fit

This pattern sits in the 81% tail relative to the top answer. Reach for it when your scenario closely matches the question title; otherwise browse the Access VBA archive for a higher-consensus alternative.

What changed between 2009 and 2026

The answer is 17 years old. The Access VBA object model has been stable across Office 2013, 2016, 2019, 2021, 365, and 2024/2026 LTSC, so the pattern still compiles. Changes that might affect you: 64-bit API declarations (use PtrSafe), blocked macros in downloaded files (Mark-of-the-Web), and the shift toward Office Scripts for web-first workflows.